One day at school, she and Chuck Clayton had a brief discussion in the library, Ethel assisted him with a math problem, and that was all. However, Chuck began to spread a rumor that he and Ethel engaged in sexual acts. Following that, someone wrote "sloppy seconds" on Ethel's locker.
Ethel joined forces with Betty Cooper and Veronica Lodge after learning that Betty was looking around school for female students who were also slut-shamed by Chuck Clayton and his posse. Ethel then volunteered to go on record with her story, she told them that after a short conversation with Chuck in the school's library, he went on to ruin her reputation by spreading rumors of him and her together. Betty sympathized with her, feeling bad that Ethel had to go through such an experience. But that's wasn't all, they also keep score of each conquest, which earns them a point, they keep all this hidden within a secret playbook, according to Ethel. And due to lack of evidence, Mr. Weatherbee's hands are tied, meaning that he would be of little help.
Upon learning from Trev Brown, the potential location of the playbook, Ethel, Betty, Veronica, Cheryl and Kevin Keller broke into the school after hours to recover it. In the book, Ethel was discouraged to learn that she is labeled as "big girl (7.5)". With the proof provided by the playbook, the ladies manage to take down Chuck and his goon squad. 
Several classmates were disturbed by Ethel's reading of an extremely dark poem, specifically Kevin and Veronica, which resulted in Veronica taking a personal interest. While Veronica was moved by Ethel's poem, she could also tell it was coming from some place dark, which led her to ask if Ethel was alright. Ethel admitted that everything was not okay within the Muggs household as her parents had been constantly fighting, but they would not tell her why. She felt as if something really bad was happening, and there was nothing she could do to stop it, like watching a slow-motion car crash. In an effort to cheer her up, Ethel was invited to lunch and pampering with Veronica and Kevin at the Pembrooke.
As promised, Ethel had lunch with Veronica, Kevin, Betty, and Hermione, however, due to all the stress she had been undergoing at home, Ethel wasn't feeling hungry. Her living situation hadn't gotten any better, as her parents were still fighting, and after some bad luck with their savings, they were going to have to sell the house. At that moment, Veronica realized that she and Ethel had more in common than she originally thought because the Lodges had also lost everything several months prior, but Veronica reminded Ethel that she still had her family and friends. Unbeknownst to either Ethel or Veronica at the time, Hiram Lodge, Veronica's father, was responsible for the Muggs' recent misfortune. So upon learning that Ethel's last name was Muggs, which the third "G" had been removed from when her grandfather came over, Hermione became fairly concerned.
The next day, Ethel was invited back over to the Pembrooke by Veronica, who gifted her with expensive clothing and jewelry, yet she didn't feel comfortable accepting them, Ethel only wanted to be friends. Just as life seemed to be getting better for Ethel, her father attempted to end his life after swallowing an entire bottle of pills. At the hospital, Ethel and her mother were greeted by Veronica and Betty, who came to extend their prayers to the family. After introducing Veronica to her mother, Mrs. Muggs discovered that her last name was Lodge, making her the daughter of Hiram Lodge, the man who was at fault for destroying the lives of the Muggs. Veronica then went on to apologize for her father's actions, which she could do something, but Ethel's mom wanted actions, not words.
The next day at school, as Ethel prepared for class, she was approached by Veronica, who was sorry for everything her family had done. Ethel explained to Veronica that she was not responsible for her father's actions, not to mention Veronica had been there for Ethel during her time of need multiple times. She then offered Veronica the desk next to her if she wanted it.
Jughead's Birthday Party
During lunch, Ethel was approached by Chuck, who was fresh off his suspension. Surprisingly, he came over to apologize, it would appear that his suspension offered him some time to reflect on his wrongdoings. Before long, Betty came over to the table and demanded that Chuck leave her alone, slamming her hand on the table in a fit of rage, but Ethel assured Betty that everything was fine.
The following night, Ethel attended Jughead's 16th Birthday Party, but before the party could even start, she found herself wondering if she could make it to the bathroom before Jughead and Betty returned from the double-feature at the Bijou, to which Kevin suggested that she holds it. Ethel peeked out the window to discover that Betty and Jughead were nearing the house, so she advised everyone to hide, and as Jughead entered, everyone jumped out. Then came the birthday cake, Ethel, Archie, Veronica, Kevin, and Joaquin surrounded Jughead as he blew out the candles.
Not long after the blowing out of the candles, the party was crashed by Chuck, Cheryl and the rest of the school, all looking to party. Later in the night, she offered Jughead a slice a cake as he passed through the kitchen, telling him that not eating his own cake on his birthday was bad luck. Unfortunately for Jughead, the entire night was bad luck. He denied Ethel's offer, and said he would see her at school.
When rumors about Midge and Moose's attempted murder spread at school, Ethel expressed her concern about a killer targeting students to a police officer sent to school to take some depositions. Ethel learned of Archie's Red Circle watch group, likely via flyers at school, and she didn't hesitate to call him when finding herself in danger. Walking home alone from school late in the evening, she noticed she was being followed by a van suspected of being driven by the Black Hood so she called Archie, who was riding with Reggie Mantle searching for him. Archie and Reggie arrived in time to save Ethel, who hid between some bushes while the mysterious driver went back and forth with his van looking for her before Archie and Reggie's arrival. She cried between Archie's arms, apologizing for not having recognized the driver, while Reggie tried to run after the van disappearing into the night.
Ethel approached Veronica in the cafeteria at school with a milkshake from Pop's and dumped it on her head. Ethel, along with others, had found Veronica guilty for the crimes that she and her parents had committed against the town.
A couple of days later, Ethel noticed Veronica's campaign for student body president, which involved bribing the male voters with kisses and cupcakes. However, as Ethel informed Veronica, she would have no such luck with those tactics in regards to the female voters. Veronica explained that she was only interested in one girl, that being Ethel. While it was long over due, Veronica wanted to make reparations. So she told Ethel to tell her father to expect a job offer very soon from her dad.
The next day, during Veronica's campaign rally, with information given to her by Josie, Ethel passed out flyers exposing Veronica for all her lies and wrongdoings. As for Veronica's half-hearted bribe with a job offer for Ethel's father, Ethel wasn't interested.
Ethel and Kevin sang "In" throughout the halls before running into the auditorium with Archie, Veronica, Betty, Cheryl, Toni, Josie, Midge and Moose. They got on stage, where they continued to sing and dance before being joined by Fangs, the assistant director. The cast then began introductions, starting with Archie who portrayed "Tommy Ross", the boy next door. Betty played "Sue Snell", the good girl. Veronica portrayed "Chris Hargensen", the mean girl. And Cheryl would be playing the iconic role of "Carrie White". As for who would be portraying, "Margaret White", Carrie's mom, that role went to Alice Cooper, which came as a surprise to almost everyone. Kevin explained that while her casting was untraditional, to him, there's nothing more amateur than age-inappropriate casting. Alice was both looking forward to playing Margaret and spending more time with Betty. Chuck Clayton joined them late after mistaking that rehearsal was in the music room.
Cheryl interrupted the rehearsal after hearing whisperings that some of them, mainly Ethel and Josie, didn't think she was fit to play the role of Carrie White. So to settle the matter, she began to sing "Carrie" to prove them wrong. After hearing Cheryl's performance, all doubts surrounding her casting were no more. Ethel, Josie, Veronica, Betty, Alice, Toni, Midge, Moose, Archie, Jughead, Kevin, Fangs, and Chuck gave Cheryl a round of applause. As Cheryl headed back to her seat, a heavy sandbag falls from above and nearly crushes her.
Ethel was Suspect #1 in Betty and Jughead's case to solve who wrote the letter pretending to be the Black Hood. In the student lounge, Betty tried to bait her. Betty accused Cheryl of always taking things she shouldn't, like the role of Carrie, to see if Ethel would agree. Jughead filmed from just outside the lounge as this unfolded. However, Ethel did not bash Cheryl, instead, she thanked Betty for the compliment of considering her to be a better fit for the lead role. Betty continued. For Kevin to cast Cheryl as Carrie without even letting Ethel audition, Betty wondered if that made Ethel angry. Ethel replied that she was born to play Carrie White. So to not be given a shot at it makes her angry. Unfortunately, Ethel noticed Jughead by the window and realized that she was being filmed and interrogated. She told them that she's not a violent person and that she would never harm anyone for her own benefit.
Ethel, Toni, Veronica, Betty and Chuck rehearsed in the auditorium, where they sang and performed "The World According to Chris". Everyone was highly impressed with Veronica as they applauded the routine. Betty credited Veronica's performance to her being the literal embodiment of Chris, the character she's portraying. Never had a role been so perfectly type-cast, Betty remarked.
Due to some unforeseen circumstances, Kevin informed Ethel, Toni, Archie, Veronica, Jughead, Fangs, Alice, Moose, Midge, Betty, Chuck, and Josie that Cheryl will no longer be playing Carrie. When they asked why, Kevin simply replied that Penelope Blossom wasn't much of a stage mom. In the meantime, Cheryl's understudy would assume the role, that being Midge, who Kevin appointed after the sandbag incident.
Opening night, in the dressing room, Ethel, Toni, Archie, Betty, Veronica, Kevin, Midge, Moose, Kevin, Alice, and Chuck sang "A Night We'll Never Forget". Afterward, she caught Jughead in her dressing room. Inside her dressing room, he found cut-out magazines, with letters missing, which Jughead surmised was used for the Black Hood's letters. Jughead concluded that Ethel was behind the threats as initially suspected, but Ethel ensured him that he had it all wrong. She cut the letters out the magazines for her vision board so she claimed before kicking him out.
The crowd was packed when the play began, and Alice started to sing "Evening Prayers". When Alice cued Midge, the curtains raised only to reveal that Midge had been murdered by the Black Hood. She had been stabbed with knives and scissors and pinned to the wall. On the wall, written in blood was a message. "I Am Back From The Dead. All Those Who Escaped Me Before Will Die... B.H" When Alice screamed in fear, the crowd realized that this was not part of the play and the auditorium erupted in panic and chaos.
The town gathers for Midge's funeral to pay respect. Cheryl sings a song in Midge's honor. She and the rest of the River Vixens are dressed in an all-black cheerleader uniform. Midge's death has seemingly taken a great toll on Riverdale, Mrs. Klump and Moose especially. Ethel stands alongside Mr. Weatherbee and the Blossoms as the service commences.
After learning about the letters from Jughead, the Sheriff turns his attention towards Ethel, who cries during interrogation. She admits that she was jealous as Cheryl often gets her way, but she never hurt anyone.
Ethel is approached in the student lounge by Betty and Jughead. The confront her over the twig doll she left in Ben's hospital room. Ethel questions where he got it from, but when Jughead asks what she was doing in Ben's hospital room, Ethel tries to leave. However, Betty pleads with her to cooperated as they're only trying to figure out what happened to Ben, Dilton and the missing scout. Jughed wonders if the twig doll is the Gargoyle King, but it's not. According to Ethel, it's the opposite. She made that talisman to protect Ben. When Betty asks how Ethel and Ben knew each other, Ethel replies that he's her boyfriend. They just started dating that summer and spend most of their time in Dilton's secret bunker in the woods. Given this, Jughead and Betty present Ethel with a ultimatum; either she show them where the bunker is located or they go to Sheriff Minetta with this information. Ethel caves, telling them that they'll meet up at Fox Footbridge after dark.
Ethel is confronted yet again by Betty and Jughead after she blew them off and withheld the location of the missing adventure scout. Even more concerning, she and Ben aren't really dating, but Ethel insists that they are in love. Betty attempts to explain that they were simply role playing, but to Ethel, it was real. Betty and Jughead are trying to help her but she first has to stop lying to them. When Ethel maintains that she's not lying, Jughead threatens to take her to the Sheriff Station, where she can repeat her truth on record to Sheriff Minetta. Ethel explains that if any of them talk to the adults, the Gargoyle King will get angry. Dilton tried to talk to Jughead and look what happened. Before Ethel can continue, she begins to have a seizure mid-sentence. Jughead yells out to Weatherbee before calling an ambulance. All the while, Evelyn watches from the doorway as this unfolds.
Ethel is approached by Betty and Jughead as she sits i the classroom alone. This is the first time they’ve spoken since the incident in the student lounge and so she informs them that she’s been given medication to prevent the seizures. She’s been having them multiple times a day. Jughead apologizes if he or Betty did anything to trigger her seizures as they were only trying to help, like they were trying to help Ben when he threw himself out of a window, Ethel remarks. Betty asks if Ethel had any visions when she collapsed. Unfortunately, Ethel can’t recall. Betty then inquires about her friendship with Evelyn Evernever, to which Ethel replies that Evelyn’s been helping her get better so that she can titrate down her meds. Betty questions whose idea this was, Evelyn’s or her dad’s. Before Ethel can respond, Betty asks if Ethel has ever met Edgar Evernever. She doesn’t answer the question directly but instead suggests that Betty look into Evelyn’s peer support group if she’s so curious. Principal Weatherbee gave her permission to start a student chapter of the Farm at Riverdale High.
Jughead then tells Ethel that before Ben killed himself, he mentioned reuniting with Dilton in the Kingdom, leading him to his question, if Gryphons & Gargoyles has a rule book or player’s manual. Ethel admits that one does exist though they refer to it as the scripture. However, she isn’t allowed to reveal to Jughead whether or not she owns a copy as he is not worthy of the King’s scripture. Jughead replies that he wants to be worthy and that he would like for Ethel to show him how. Ethel agrees to show Jughead, but him alone as Betty will never be worthy. They arrange a meeting for tomorrow night in Dilton’s bunker.
As planned, Ethel and Jughead meet up in Dilton’s bunker. She welcomes him to his first game, his entry point to the realm of Gryphons & Gargoyles. The magical kingdom of Eldervair. First things first, Jughead must pick his character. He’s given the choices of the Radiant Knight, Arcane Invoker and Hellcaster. Jughead chooses Hellcaster, which was also Ben’s avatar. Ethel was supposed to ascend with him but he betrayed her and finished the game with Dilton instead. Jughead then picks a quest card and they proceed with the game.
Ethel and Jughead continue their game of Gryphons & Gargoyles. Jughead crosses the old footbridge to find two doors. One is made of shimmering gold and the other is just maple wood. Jughead chooses door number two, which proves to be a wise choice. He enters a secret chamber and is now standing in the middle of a circle composed of gryphon bones. Two chalices sit before him. Ethel then unveils two real chalices. In order to prove his worthiness, he must drink from one of the Sacred Goblets, which Jughead is adamantly against as one of the chalices contains poison or as the game refers to it, gargoyle blood. Jughead must flip a coin to determine which cup he drinks from. He reluctantly agrees, but only if Ethel hands over the scripture afterwards. Jughead flips the coin and is forced to drink from the gryphon marked chalice. He guzzles it down and is seemingly fine, with nothing more than blue coloring on his lips to show for his life threatening decision. Before handing over the rule book, Ethel tells Jughead that he must kiss her first according to the scripture. The Hellcaster kisses the princess or he doesn’t get the treasure, it decrees. Jughead kisses Ethel and takes the book. While Jughead’s reading the rule book, Ethel chugs the chalice filled with poison. Jughead attempts to stop her but she has already consumed it.
Ethel is taken to Riverdale General Hospital by Jughead. When she wakes, Jughead reveals that she’ll be fine as she was given the antidote in time. Ethel finds herself locked to the bed. It’s protocol for anyone on suicide watch. When her parents arrive, Jughead wants Ethel to tell them everything about the game, but Ethel refuses. She won’t tell them and neither will Jughead because if he does, she’ll lie and say he mixed the fresh-aid. Jughead tells her that the game is over, but Ethel retorts that it’s only just beginning. Jughead has proven himself much to Ethel’s pleasure. She told the Gargoyle King that Jughead was worthy enough to spread his gospel. Jughead states that the King won’t hurt anyone else and that he’ll see to it that the scripture doesn’t end up in anyone else’s hands. Ethel grabs Jughead’s hand and thanks him for helping her to finish the game.
Much later, Ethel speaks to the Gargoyle King. She did as he asked by spreading his gospel. Soon, everyone will join them. Ethel then bows down before the Gargoyle King.
Since being released from Riverdale General Hospital, Ethel was checked into the Sisters of Quiet Mercy. She is now Betty's roommate. Sister Woodhouse thought Betty might benefit from having a roommate who is familiar with the system around there. Ethel hangs her warrior board on the wall. It’s a collage. A visual collection of her destiny. It also helps her manifest her goals. Ever since Ethel arrived at the Sisters, she claims to have been having conversations with the Gargoyle King. Betty wants Ethel to introduce her to the Gargoyle King, but Ethel can’t as that’s Sister Woodhouse’s job. The Sisters take patients into the Gargoyle King’s chamber when they misbehave. The other girls are scared of him, but Ethel isn’t. Betty asks for the location of the chamber, but that too is Sister Woodhouse’s job.
Betty then changes the subject to Jughead, who she remarks that Ethel would tell. Speaking of Jughead, Ethel reveals that she and Jughead shared a kiss, which Betty is already aware of as Jughead told her how Ethel blackmailed him into kissing her. Ethel becomes upset, accusing Betty of always acting as if she’s better than her. As well as her "shallow friends" acting as such. Ethel states that the Sisters isn’t like being at Riverdale High. The rules are different and Ethel is the queen bee. If Betty wants to get better, she has to change her attitude and be honest with herself and others. Ethel wants to start with the fact that Betty threw her Fizzle Rocks in the trash. Betty apologizes. She says that she wants to be Ethel’s friend and asks that Ethel keep this between the two of them. Ethel agrees.
Ethel catches Betty trying to sneak into what she believed to be the Gargoyle King's chamber. Betty comes up with a excuse, claiming that she was looking for the medical archives. The lie goes that Sister Agnes sent her to fetch some files and she got lost. Ethel tells Betty that only the infirm are allowed in the infirmary. She and Ethel then return to their room.
Later, Ethel invites Betty over to play G&G with the other patients. Betty then provokes an altercation with Ethel in order to gain access to the infirmary, unbeknownst to Ethel. She addresses how Ethel is a fake friend for kissing Jughead. Ethel replies that she only kissed Jughead because the Gargoyle King wants them together. She states that Betty is jealous that both she and Jughead are worthy while Betty will never be. Furthermore, she’s never going to meet the Gargoyle King. Betty then fakes have a seizure. Gaining the attention of the Sisters. Sister Woodhouse comes to Betty’s aid, calling for a nurse to take Betty to the infirmary.
Ethel, Sister Woodhouse, and two orderlies catch Betty trying to break put through a door in the basement. Betty is held down as as Sister Woodhouse force feeds her Fizzle Rocks. As this occurs, Ethel recites a phrase. "My King. My savior. Guide me through the night. Bless me with your darkness, gift me with your flight." Ethel accompanies Sister Woodhouse as she takes a barely functional Betty to see the Gargoyle King. Betty is pushed inside the chamber and the doors shut behind her.
At the Sisters of Quiet Mercy, Ethel leads a quest in a game of G&G. Betty joins her. Sister Agnes then comes over to give them their daily ration of Fizzle Rocks.
Ethel confronts Betty after overhearing her conversation with the other patients, claiming the Gargoyle King tells her all his secrets and gives her personal quests. Betty persists with her claims of having gotten to know the Gargoyle King, which only angers Ethel. Just to get under Ethel’s skin, Betty lies and says that the Gargoyle King called her his favorite. Ethel calls Betty out, under the suspicion that Betty’s lying, just to make fun of her. Betty denies doing anything of the such. She then baits Ethel into unlocking the Gargoyle King’s chamber. Once Ethel unlocks the door, Betty pushes her inside and locks her in. Her reason for doing so is to convert Ethel. Betty explains that the Gargoyle King isn’t real and that the Fizzle Rocks given to them by the Sisters are causing them to hallucinate. Once the drug wears off in a few hours, Betty is certain Ethel will see the truth. Until then, Ethel will remain locked up. Inside the chamber, Ethel sees what she believes to be the Gargoyle King, and screams out in fear.
Betty returns to the chamber hours later to check in on Ethel. Now that Ethel has come down from her high, she realizes the Gargoyle King she thought she saw was really just a gargoyle statue. Betty explains that the Sisters feed them drugs to make them susceptible to visions that they suggest. They let the patients play the game and use their delusions to scare them into submission. Ethel still has doubts, but Betty assures her this is all true. The Sisters are in league with Hiram Lodge as well. Betty thinks that he’s paying the Sisters to test his drugs on patients. Even if this is true, Ethel recalls seeing the Gargoyle King in real life, before being admitted into the Sisters. She saw him in her hospital room. Betty admits that she saw him too. Or at the very least someone dressed as him. At any rate, it doesn’t change the fact that in there, it’s just a statue. Betty now needs Ethel help to learn all that Sister Woodhouse knows about G&G. If they know more, they can prevent more deaths like Ben and Dilton’s from happening again.
While Ethel distracts Sister Agnes, Betty sneaks up behind Sister Woodhouse with a sharpened stick and holds it to her neck, threatening to hurt her unless she complies.
Ethel and Betty tie Sister Woodhouse to a chair inside the chamber. Enraged by her entrapment, she threatens to strap them to their beds and electroshock the sin out of them. Betty’s seen real darkness, so monsters don’t scare her and neither does Woodhouse, Which is why she couldn’t break Betty. Betty reveals that she knows all about the Sisters’ scam and alignment with Hiram Lodge, how they’re using the patients as test subjects for his new drugs. Sister Woodhouse reveals that Hiram is a generous donor and believer in their mission. Ethel questions if by mission, if Woodhouse is referring to G&G and how they use it and the Gargoyle King to scare the girls and torture children.
According to Sister Woodhouse, the children that come in are broken and it is her duty to mix them using whatever tool necessary, including Gryphons and Gargoyles, which they created in a way. Misbehaving children have been brought down to the chamber since the asylum opened. That gargoyle statue scared them into submission. Some of the more disturbed patients created a fantasy world, a game of sorts, to cope with the fear of the one they named the Gargoyle King. The Sisters simply embraced it as a therapeutic tool. It worked because it embeds itself in the minds of the players. It makes them complacent and focuses them. If that’s true, Betty wonders how the game got out into the real world. Sister Woodhouse claims it was never meant to leave the asylum as it is too powerful. A game made of madness that the Sisters helped nurture, Ethel remarks. And now Ben and Dilton are dead. Betty insists that Woodhouse tell the police what she told them about G&G as well as Hiram Lodge’s donations. However, Sister Woodhouse only answers to one authority. With Sister Woodhouse’s keys, Ethel and Betty plan to escape and take the other patients with them. Sister Woodhouse however doubts they’ll leave of their own free will. She then proceeds to scream out for help as Ethel and Betty lock her inside the chamber alone.
Much to Ethel and Betty’s surprise, the patients don’t want to leave. They feel safe there. They play G&G and the Sisters give them candy. Sister Woodhouse was right. They’re all brainwashed just as Ethel was, forcing her and Betty to reassess the situation. Betty refuses to leave them behind, not to mention all the kids in the gay conversion wing. Betty devises a plan to use the game, turning their escape into a quest. The Gargoyle King inspires fear and Betty wants to give them the opposite, that being the Gryphon Queen. The patients gather around Ethel as she starts the quest. She tells them that their goal is to escape from the Gargoyle King’s fortress. And to help them do so is a Queen to lead them into the light, that Queen being Betty, who while dressed up as the Gryphon Queen, tosses on the floor the head of the gargoyle statue, stating that the King is dead. As planned, the patients play along, escaping the asylum with Betty and Ethel leading the charge.
Ethel and Betty, while guiding the patients to freedom, have not the slightest idea what they’ll do with them now that they’re free. Alice pulls up. With all hell breaking loose, she had come to get Betty out of the Sisters. While Alice is just in time, it’s not just Betty she’ll be taking with her as the patients needs somewhere to go as well.
Ethel hides in the bunker as she fears the Gargoyle King wants to kill her for failing her mission. Ethel admits to Jughead, who enters the bunker, that she’s the one who sent Ricky with the letter from the Gargoyle King that was addressed for Betty at Prom. Jughead is upset that Ethel led her right to the Gargoyle King and the Black Hood. He thought Ethel had quit playing after Betty saved her from the Sisters of Quiet Mercy. Betty saved Ethel from the Sisters’ false King, but Ethel later rejoined the true Gargoyle King in the woods. When she came back to him, he put her in charges of his Lost Boys, i.e. the adventure scouts. Jughead demands to know who the Gargoyle King is, but Ethel can’t betray his trust, even after she just said that he’s trying to kill her. Despite it all, Ethel still loves him. Jughead calms down. He tells Ethel it’s okay. However, she and the Lost Boys aren’t safe in the woods, so Jughead wants to move them elsewhere.
Ethel tells the Lost Boys to stand down as Jughead, the Hellcaster, is on their side and has come baring good news. Ethel claims their quest is complete. Jughead notices that Ricky is missing, who he suspects has left to report back to the Gargoyle King and the Black Hood. When they learn that Jack, the youngest of the Lost Boys is missing, Jughead and Ethel set off the find him.
Ethel and Jughead arrive at the junkyard in search of Jack. They find him on the broke down bus. Unfortunately, they are not alone. The Black Hood arrives right behind them. Jughead covers Ethel’s mouth with his hand and tells both her and Jack to stay quiet and crouch down in between the seats, in hopes that the killer will pass them. However, the Black is already aware of their location, slamming on the hood. He then gets on the bus, forcing Ethel, Jughead, and Jack to force their way out the back door. Jughead then props something up against the door, preventing the Black Hood from getting out the back. He then races to the front door, barricading that one as well, locking the Black Hood in.
After narrowly escaping the Black Hood, Jughead and Ethel head to the sheriff station. Ethel asks about the Lost Boys, and FP informs her that they’ve been assigned a deputy until the Gargoyle King and Black Hood are caught. As FP exits, Jughead assures Ethel that everyone is safe and that they’ll find Ricky. Ethel thanks Jughead for all his help. She hugs him, and as a reward, Ethel reveals to Jughead the identity of the Gargoyle King. She claims he is Jason Blossom.
Ethel is confronted by Jughead about the videotapes she dropped off at the sheriff station. He informs her that one of them was a snuff film of someone dressed as Betty murdering someone dressed up as him with a rock. Ethel insists that she had no knowledge of this. She’s just trying to keep her head down and make it out of Riverdale in one piece.
Jughead confronts Ethel with the tape that Charles found in her home; the sex tape of him and Betty that was originally filmed by Bret at Stonewall Prep. He questions where she got the tape from. Ethel reveals that there’s a secret place in the back of the Blue Velvet Video store called the "Scarlet Suite." There, you can find tapes of all kinds, including sex tapes and snuff films. Ethel explains that the video was called Ponytail Playmate and that she had no idea it was of him and Betty. She only kept it to make sure no one else would find it.
Ethel has pale skin with lots of freckles and light ginger hair. She is tall and a little on the heavier side, being labeled by the Riverdale Bulldogs as "big girl". She usually wears a blouse, paired with a thin sweater and a long skirt, and always wears a headband with a bow on it.
Ethel is a shy and quiet girl, the type to avoid problems and controversy. She keeps to herself and is heavily focused on school work. Beneath all that is a depressed and lonely young lady. The troubles that her family is currently facing certainly do not help. Despite her generally positive attitude, Ethel isn't afraid to get even. She is known to be quite underhanded and rude under the right circumstances, such as when she dumped a milkshake on Veronica, and later teamed up with Josie to ruin Veronica's chance of being school president.
Ethel is of Dutch descent on her father's side. Their family name was originally spelled "Mugggs" but lost the third "G" when Ethel's grandfather, Manfred Mugggs, immigrated to the United States.
Outside of The CW's Riverdale, Muggs is not a traditional "Dutch" surname, as the word, either spelled Muggs or Mugggs, has no meaning within the Netherlands. Mugg(s), however, is of English origin, originating from Somerset, England.
In the Archie Comics, Ethel is infatuated with Jughead to different degrees depending on the story, which has been reflected in the series since Jughead saved her from the Black Hood.