Marcus was a student at San Ramon Middle School and the nephew of Britta Perry. He and his classmates visited Greendale to see a special performance of an anti-drug play featuring the study group. Although very young, he has a premature and disturbing interest in the opposite sex. Marcus' first and so far only appearance was in the Season Two episode "Celebrity Pharmacology 212". He is portrayed by actor Justin Marco.
In the study group's second year at Greendale, Annie had produced an anti-drug play for San Ramone Middle School students. The entire study group were featured players, and Britta's nephew Marcus was one of the kids attending the performance. He texted his aunt and asked her if she was actually going to wear a cat costume. At the time Britta accidentally left her cell phone behind in the study room. His text ended up being read and answered by Jeff. He had earlier teased Britta about her refusal to try "sexting" her paramours. Jeff decided to respond to Marcus as Britta, unaware that he was her nephew. "Britta" flirted with Marcus, by promising to reveal what was under "her" costume. Abed questioned Jeff's actions, but his concerns were denied.
The day of the play Jeff learned from Britta, who was completely unaware of the previous text messages, that Marcus was her nephew. She was surprised when Marcus had sent her a text telling her how excited he was to see her because she had thought he didn't like her. Britta was confused by an emoticon Marcus had sent and showed it to a Jeff who recognized it as an emotipenis. He had Britta go change for the play while he held onto her phone to do damage control. Jeff tried to get Abed to help him, but he refused. Jeff sent more texts, but this only encouraged Marcus more. Marcus even sent a personal photo to Britta's phone, which Jeff found offensive. While Jeff performed in the play, he kept texting Marcus, hoping to resolve the situation without Britta finding out.
Jeff spotted Marcus in the audience, texting him back but was unable to deal with the problem due to Pierce's hijacking of the play. Once the play concluded, Jeff confronted Marcus, who had flowers for his aunt. Jeff introduced himself to Marcus as Britta's boyfriend hoping to scare him, but Marcus told him that she started it and was just as into him, as he was into her. Jeff admitted he was the one who sent the texts, grossing Marcus out. Jeff then admonished him for sending perverted photos to his aunt. Marcus countered, stating what he texted to an underage boy was just as reprehensible. They both argued that they weren't responsible for their actions, since they were unaware the identity of the person they were texting. Marcus agreed to remain silent if he got his aunt's bra, which Jeff managed to retrieve for him ("Celebrity Pharmacology 212").