I don't know, but guys like us, like you, in a town like Riverdale, we don't have a lot of options. So, even if something bad could happen, we go for it, 'Cause what if, for ten minutes or maybe even just for two minutes, we're not alone.
Moose is a student at Riverdale High School and a member of the varsity football team, the Riverdale Bulldogs. He is secretly attracted to men, which led to his relationship with Kevin Keller. However, Moose's reluctance to come out prevented this relationship from ever truly developing. Although, they do share a kiss in the restroom.
He, along with Midge, were attacked by the Black Hood though only Moose was harmed as he shielded Midge from the gun fire. With the help of Kevin, he was rushed to a hospital where he later made a full recovery.
It is currently unknown whether or not Moose grew up in Riverdale. There's also nothing known of his home life, such as his family. However, his closest friend appears to be Reggie Mantle, as they are almost always together.
According to Kevin Keller, Moose approached him at the back-to-school Semi-formal with a proposition, apparently, some time during the discussion, Moose showed Kevin a "certain appendage", one he described as being "horse-like". Following his conversation with Kevin, he spiked the punch bowl and got drunk with Reggie. After the Semi-formal, he and Kevin headed to Sweetwater River. Whilst arriving, Moose stated that he was not gay. As the two prepare to go skinny-dipping, Kevin stumbles upon the body of Jason Blossom at the shore. 
Moose insists that he be partnered up with Kevin during class, as they have something to talk about. He wanted to arrange another meet up with Kevin on Saturday night. However, Kevin declines as Moose has too many secrets, he then suggested that Moose stick with what he knows best, which is girls. Later that day, in the student lounge, Reggie questioned Moose on what he and Kevin were doing by the river, and why the cops didn't come looking for him, since they found the body. 
As the football team ran drills during practice, Moose stood along the sideline of the field with Coach Clayton and several other players. 
Moose, Reggie, and several other members of the Riverdale Bulldogs taunted an anxious Archie, as he got on stage to perform his audition song for the annual Variety Show, the severity of which resulted in the players momentarily appearing in werewolf masks. 
Construction & Carousing
Having learned that Andrews Construction, the company that is owned by Archie's father, was facing great misfortune, Moose, Archie, Jughead and Keller volunteered to assist him in the SoDale project and keep him on schedule until he could find a real crew. Unlike everyone else, Moose rather enjoyed the hard labor, he preferred working on the construction site instead of the weight room. The day had come to an end as the boys returned to the trailer, but Moose accidentally left his phone back on the project site, as he returned to retrieve it, he stumbled upon two thugs damaging Andrews construction equipment. They then turned their attention to Moose, knocking him to the ground and beating him bloody, before warning him that they'd return if construction for the SoDale project didn't come to an end. Sheriff Keller arrived shortly after to get their statements, while Fred believed the men to be associates of Cliff Blossom, Archie suggested that they could've Southside Serpents, who were angry due to losing their territory.
The next day, with the help of Kevin's boyfriend, Joaquin, who was also a Serpent, Moose, Archie and Kevin infiltrated a known hang out of the Serpents, called the Whyte Wyrm. Once inside, Moose directed his attention towards a patron in the bar that could've potentially been one of his attackers. While the original plan was to find the thugs responsible and call Sheriff Keller, Archie took it upon himself to confront the Serpent, which didn't end well as they were greatly outmanned. Luckily, the fight was brought to an end by FP Jones, the leader of the Serpents and Jughead's father. He removed the boys from the bar, and set them home before they could cause any further trouble. 
A large group of students. Moose included, were led by Cheryl and Chuck as they crashed Jughead's 16th Birthday Party at Archie's house. With a keg over his shoulder, Moose wondered where Archie wanted them, which he replied one in the kitchen and one in the backyard. Then he and Cheryl took the dance floor, where they danced and kissed. He was also there to bear witness to Archie's altercation with Valerie, which he, Chuck and Cheryl had a good laugh about. Unfortunately, the party abruptly came to an end as a fight between Jughead and Chuck resulted in FP sending everyone home.
After learning that Riverdale High's former music teacher, Ms. Grundy, was murdered in her Greendalehome the previous night, Moose and Midge attended Retro Night at Pop's Chock'lit Shoppe, where they scored some Jingle Jangle from Reggie in the diner's parking lot. Unbeknownst to them, they were being photographed by Alice Cooper. Later that night, Moose and Midge drove out into the woods, where after taking the Jingle Jangle, they began kissing in the car. However, before they could go any further, a man wearing a black hood appeared from the darkness, shining a flashlight into the car, and firing several shots.
Moose was joined at Riverdale General Hospital by Archie and Reggie after being shot multiple times by the Black Hood. Fortunately, he would survive the attack and Midge was left unharmed due to his heroic actions in which he used his own body to shield her from the gunfire. Archie assured him that he saved her life. After stealing his dessert, Reggie asked Moose if his nurse was attractive. If so, he ran the risk of getting a boner during a sponge bath. Moose laughed in response. Archie then questioned him about the shooter's appearance, mostly regarding the black hood he wore to conceal his identity and the color of his eyes, the answer to which Moose did not provide, as he was cut off by Midge, who entered the room, and described the shooter's eyes as being blank, comparable to the eyes of the devil or Michael Myers.
A couple days later, Moose received a visit from Kevin Keller, who he informed that Midge wanted to thank for saving their lives. He wondered what Kevin was doing in the woods, to begin with, though Kevin turned the question back onto Moose, asking him what he was doing in the woods with Midge, beyond taking Jingle Jangle, which everyone had already been made aware of. Moose claimed that it was Midge's idea. She had a wilder side that she occasionally indulged in. While he had genuine feelings for Midge, he wasn't entirely sure that they were a match. Noticing a trouble looked on Kevin's face, Moose asked him if everything was alright. Kevin replied that he had been making bad decisions lately and lying to his father. He knew it was dangerous, but he couldn't stop himself from sneaking around the woods at night, looking for hook ups. Its as if he didn't even care about his own well being. Moose explained that this was due to the lack of options for guys like them in Riverdale. So, even if something bad could happen, they go for it because what if, for however long, they're no longer alone. As Kevin headed out the door, Moose told him that he could stay or come back at a later time if he wanted to hang out or talk.
In the days leading up to Christmas, Moose and Midge entered the student lounge at school to find Archie, Betty, Cheryl, Kevin, Veronica, Jughead and Josie opening presents as part of a Secret Santa gift exchanged. Moose and Midge were welcomed back by hugs from Josie, Reggie, and Kevin.
Moose was approached by Kevin while at his locker to see if he wanted to accompany him to the Bijou to watch the 2018 American romantic comedy-drama film Love, Simon. Unfortunately for Kevin, Moose had already planned to go with Midge though he did invite Kevin to tag along, claiming that Midge knew all about them. Supposedly, she was cool with it, but Kevin passed on the offer nonetheless.
The following night, Moose and Midge stopped by Pop's Chock'lit Shoppe. There, they found Kevin eating alone. So Midge invited him to join her and Moose in their booth. Midge assumed that Kevin would be meeting someone at the Bijou, but unfortunately, he wasn't. Which Midge found to be unacceptable. She offered to help him find a date, suggesting one of the new Southside Serpents that had recently transferred to Riverdale High following the closing of Southside High. She had heard that at least one of them was gay, Fangs Fogarty. However, Kevin explained that he didn't think he could date someone named "Fangs". Moose interjected that Kevin should at least give Fangs a chance since he was attractive though Midge disregarded his comment. She then asked how Kevin and Moose became friends. Though Moose and Kevin came to know one another through pre-planned sexual encounters, Kevin told her that they were lab partners in Biology.
Editor's Note: While actors Cody Kearsley, Casey Cott and Moses Thiessen do appear in the following scene, they do not portray the characters whom they are credited for i.e. Moose Mason, Kevin Keller and Ben. Instead, they portray young men who eschew from socializing with women to spend time together.
During movie night at the Sisters of Quiet Mercy, the patients were forced to watch a film about homosexual deviance that outwardly starred Moose and Kevin. These two seemingly all-American boys chose to abstain from going to the diner with their friends to have chocolate phosphates with the girls, and instead headed down to the river, where they undressed and went for a swim without clothes.
Moose ran into the auditorium with Cheryl, Toni, Betty, Veronica, Archie, Josie, Ethel, Kevin and Midge. 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 rehearsal after hearing whisperings that some of them, mainly Ethel and Josie, didn't think she's fit to play the role of Carrie White. So to settle the matter, she began to sing "Carrie" to prove them wrong. Her singing removed all doubt as Moose, Midge, Archie, Veronica, Betty, Ethel, Josie, Alice, Toni, Jughead, Kevin, Fangs, and Chuck gave Cheryl a round of applauded. As Cheryl headed back to her seat, a heavy sand bag fell from above and nearly crushed her.
Toni, Veronica, Ethel, Betty and Chuck rehearsed in the auditorium, where they sang and performed "The World According to Chris". Moose, Midge, Archie, Fangs, Kevin and Jughead are 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 Moose, Midge, Toni, Archie, Veronica, Jughead, Fangs, Ethel, Alice, 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 sand bag incident.
Opening night, in the dressing room, Moose, Midge, Toni, Archie, Betty, Veronica, Kevin, Alice, Chuck and Ethel sang "A Night We'll Never Forget". Afterward, Moose appeared to be in a bad mood as he passed Jughead in the hallway.
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 Loss of a Loved One
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 all-black cheerleader uniform. Midge's death has seemingly taken a great toll on Riverdale, Mrs. Klump and Moose especially. Moose stands alongside Reggie, who consoles him as the service commences.
Afterwards, Sheriff Keller begins his investigation into Midge's murder, starting with interrogating everyone involved in the play. Sheriff Keller asks Moose if he remembers the last thing he said to Midge, but Moose claims to have no recollection, stating that his last words to her were probably something casual or stupid.
If what happened to Midge taught them anything, it's that no one is safe and that the town needs the Dark Circle. So Archie rallies the guys in hope that they will join him. This time around, they'll even have the Sheriff's support. Kevin is there as well, but only to help catch the guy that took his father's job. Moose has a confession to make. The night of the musical, he and Midge got into an argument because she admitted that she was seeing someone else, a Southside Serpent is all he could get out of her. Reggie is outraged. Reggie knew the Serpents would do something the second they stepped foot into the school. When Kevin asks why Moose didn't say anything before, he explains that he didn't want to become a suspect. Archie wants to go to the authorities with this information, but Reggie would rather find out on his own who the Serpent is that was hooking up with Midge.
Moose, Kevin, Reggie, Archie and the rest of the Bulldogs interrupt the Serpents' Swords & Serpents meeting. They've come for answers to who was hooking up with Midge. Reggie immediately points his finger at Sweet Pea, who does not take the allegation lightly. He claims that while he didn't know Midge, he completely understands why she wouldn't want flees from the mangy Bulldogs. Reggie is angered by Sweet Pea's insult and pushes him. This nearly leads to a fight. Thankfully, Archie and Jughead are there to keep their respective sides at bay.
Leaked behind the scenes documentary footage of Fangs in Midge's dressing room on the night of the Musical surfaces. With this, Moose, Kevin, Reggie and the rest of the Dark Circle begin their search for Fangs as they are certain that he is Midge's killer. It doesn't take them long to find him. On one end of the hallway stands the Dark Circle, on the other ends stands Sheriff Minetta and his deputies. Fangs insists that he didn't do anything, but when he tries to run, Sheriff Minetta wrestles him to a wall as he resists arrest. In doing so, a switchblade falls out of Fangs' pocket. Seeing this, Sheriff Minetta slams Fangs onto the ground before cuffing him.
Halfway across town, Reggie leads Moose, Kevin and the Dark Circle as they set a dumpster on fire and slash all the tires just outside the Whyte Wyrm.
A meeting of the Dark Circle is called after Archie heard about what they did on the Southside by setting dumpsters on fire and slashing tires. Reggie claims they were celebrating Fangs' arrest. Archie counters that his wrongful arrest isn't something to celebrate. However, Kevin argues that Fangs had a knife on him, making him look very guilty. Archie refuses to argue with them anymore. With that being said, he announces that the Dark Circle is officially disbanded. However, Reggie, Moose and Kevin have no intention on stopping. It's not Archie's decision to make as Hiram is the one paying them. He even suggested that they go out and have a little fun. While Archie may have started the Dark Circle, Hiram stated that it is now Reggie's.
Moose, Kevin, and Reggie later attend the Mayoral debate at Town Hall between Fred Andrews and Hermione Lodge until the Black Hood arrives and begins shooting
Moose, Kevin, Archie, and the Bulldogs meet in an alleyway. None of them seem to know of Reggie's whereabouts. He and Archie got separated when the fight broke out. Archie explains that Reggie had a gun, but Archie tackled him before he could shoot Fangs. When Kevin asks why Reggie would have a gun, Archie suspects that Hiram Lodge put him up to it. Nonetheless, they have to find Reggie as some of the Southside Serpents saw him with a gun. Moose, Kevin, and Archie head to Reggie's house while the rest of the Bulldogs fan out to find him before the Serpents do.
While Moose, Kevin, and Archie search for Reggie, Archie calls Jughead to inform him that the Serpents are trashing the town. Jughead is well aware. He surmises this is due to Reggie shooting Fangs. However, as Archie explains, Reggie didn't shoot Fangs. So Jughead needs to call off the Serpents. They just came from Reggie's house, but he wasn't there. Moose, Kevin, and Archie are now headed to Riverdale High School as that's where Reggie's mother said he was going. Jughead arranges to meet them.
Moose, Kevin, and Archie enter Riverdale High through a classroom window. Just outside the classroom, the Southsiders demolish the school in retaliation for Fangs' shooting. Archie reminds Moose and Kevin that they're out manned and unarmed. However, Moose and Kevin refuse to hide while the Serpents destroy the school. Archie agrees to join them, but only if they're organized in they're attack.
Moose, Kevin, and Archie demand that Sweet Pea and the Serpents stop vandalizing the school. As the Serpents approach, Archie swears to him that Reggie didn't shoot Fangs. He says it was Mrs. Klump, but Sweet Pea isn't buying it considering that he saw Reggie with a gun outside the station. However, as Archie points out, Sweet Pea also saw Archie tackle Reggie before he could pull the trigger. Nonetheless, whether it was Reggie or Midge's mom who shot Fangs, a Northsider put him in the hospital, where he is hanging on for dear life. Northsiders took his friend and his land. And they'll take everything if the Souhtsiders give them the chance. So now, Moose, Kevin, and Archie get to watch as the Serpents burn the school to the ground. Sweet Pea then throws a trashcan into the display case, shattering the glass. Armed with nothing more than bats and sticks, Moose, Kevin, and Archie prepare to fight off the Serpents. Fortunately for them, Mr. Weatherbee arrives with backup and a baseball bat of his own to see to the end of the confrontation. Afterward, they meet with Jughead and tell him the Serpents are gone.
Moose, Kevin, and Archie convene with Reggie at Pop's. Reggie didn't know where else to go after Hiram hung him out to dry. Just as Archie questions if Hiram put Reggie up to shooting Fangs outside the station, Southsiders supposedly pull up outside of Pop's. Archie calls Jughead to ask where he and the Serpents are at. Jughead informs him that he just brought them back to the Whyte Wyrm and Mrs. Klump's house is secure. Given that the Serpents are at the Wyrm, they begin to wonder who has just pulled up outside. At a closer look, they discover that Malachai and the Ghoulies have returned. Kevin and Moose block off the door as Archie calls the sheriff station. Unfortunately, no one answers. When the Ghoulies bust the front window, Archie goes to the roof and throws Molotov cocktails at the Ghoulies, holding them off long enough for Kevin, Archie and Jughead's dads to force them to retreat.
Moose is in the bathroom crying. He is found by Kevin. Moose wipes away his tears before revealing that all of Midge's belongings are gone. Midge's locker was trashed during the riots. All her books, stuffed animals and the notes that their classmates left her are gone. Kevin hugs Moose, hoping to console him as he reminds Moose that these are all material things and that he'll be alright. Moose then kisses Kevin, who is taken by surprise by this display of affection. Though hesitant, Kevin kisses Moose back and they proceed to make out in the restroom.
A couple days later, after Archie, Jughead and Cheryl saved the Serpents from a raid at the Whyte Wrym, Moose joins them and the rest of their classmates. The school comes together in a show support of the Southside students who are being wrongly transferred. Moose, Archie, Jughead, Josie, Veronica, Reggie, Cheryl, Toni, Sweet Pea, Kevin and many other students put on Serpent jackets and confront principal Weatherbee. Archie explains that everyone is ready to walk out. Mr. Weatherbee threatens to expel any student that does, though Archie calls his bluff. He knows that Weatherbee is a good man who doesn't discriminate, and if he isn't, Archie tells Weatherbee to expel him as he doesn't wish to be apart of that. With that being said, Weatherbee tells everyone to get to class.
Both the mayoral election and student body election are held in the gymnasium of Riverdale High. Among the voters are Moose, Josie, Pop Tate, Weatherbee, Sweet Pea, Veronica, Reggie and many others.
Moose, Kevin, Archie, Jughead, Veronica, Sweet Pea, Toni, Cheryl, and Reggie are in the student lounge when Mr. Weatherbee announces that the student council election votes are in. The new student body president of Riverdale High is Archie Andrews. The entire student body applauds his election. In unrelated news, Weatherbee also announces that for the foreseeable future, all former Southside High students will remain at Riverdale High. The entire student body applauds once more in celebration.
Moose attends the party over at the Andrews house as they wait for the votes to come in for the mayoral election. Moose, Kevin, Archie, Sierra, Veronica, Reggie, and Josie all attend. Unfortunately, Fred loses the mayoral race to Hermione. Not long after this news breaks, Hermione stops by to tell Fred that he ran a great campaign. It was close. It came down to less than 200 votes. As a show of good sportsmanship, Hermione and Fred shake hands.
The following day, Moose and Reggie watch proudly from the stands as Archie prepares to be inaugurated in the school gymnasium. However, the event goes awry when Sheriff Minetta and two deputies enter the gym to arrest Archie for the murder of Shadow Lake resident, Cassidy Bullick.
Moose is an attractive young man with tan skin, hazel eyes, and dark brown hair. He is tall, with an athletic build, due to his place on the football team. He doesn't put much thought into his choice of clothing, typically a jacket or hoodie with jeans.
Like Reggie, Moose embodies several characteristics usually associated with the stereotypical jock. He doesn't appear to be very smart nor does he seem interested in school. Football, and concealing his true sexual orientation are his biggest concerns. However, he has been known to have a more compassionate side; volunteering to help work at Andrews Construction following the exits of Fred Andrews's crew.
Moose is also very heroic, as he risked his own life to save Midge Klump, his girlfriend, from the Black Hood. Due to his sexuality, like Kevin's, he is also very understanding when it comes to relationships with other dudes, and can be very comforting to the other person when they seem to be lost.
Neither Moose nor Reggie Mantle were cut from the football team the way that Chuck Clayton and a number of other players were, when the scandal of Chuck's "playbook" broke, despite their names being clearly visible in the book.