An orange named Fido in the books and Red in the cartoon
Stephen is a student in Mrs. Jewls' class. Stephen always ends up in bizarre costumes, which the class seems to comment on. His best friend, Jason, even believes his outfits are fairly silly. However, he always ends up in them nonetheless.
Stephen is a boy with a round face and green or orange hair. His appearance changes depending on his outfit, so currently, little else is known about him. In the cartoon, he always wears an elf outfit, that has a green hat with a yellow bell at the end. Stephen has a green outfit with a black belt that has a yellow buckle. He has brown pants and dark green shoes. In the books, it is described that his normal outfit consits of a polo and a pair of jeans.
Stephen seems to be rather annoyed when people make fun of his outfits, as revealed in his chapter of the first book. He often finds himself to be somewhat of a class leader, especially after taking Myron's role as class president. He has an obsession for Halloween, which is played up greatly in the cartoon. He was the only member of the class that dressed up for Halloween, since the holiday was on a Sunday that year, and he thought the party would be on the Friday before.
In Sideways Stories from Wayside School, his chapter, "Stephen", focuses on him showing up to school in a silly goblin outfit, only for the ghost of Mrs. Gorf to appear, reassuring that since Halloween is on a Sunday, they must celebrate it on the Friday before.
In Wayside School is Falling Down, a chapter called "A Story That is Not About Socks" has Stephen show up to class in a fairly fancy outfit, only to proclaim that it has no other purpose than for standing around and looking important. He then ends up choking himself with his tie, hoping to look more important.
In the cartoon, an episode called "Be True to Your Elf" has someone make fun of Stephen's elf costume, so he tries to become Mr. Normal so he can lead the parade.