|Characters and/or events depicted in this article are a what-if version and are non-canon|
Arnold is a male student who goes to Madison Elementary School.
Arnold is a chubby and short boy who and has short orange hair and brown eyes. He wears a short-sleeved light yellow T-shirt, green shorts, red glasses and white and green shoes.
During gym class at school, he wore a yellow T-shirt and dark blue shorts.
Arnold made his debut in Goodbye and Good Riddance, where he was often seen at school with his friend Peterson. When Ben arrived from vacation, the boys showed an interest in the space heroes, but did not know that Tennyson was behind them. When the hero became involved in their discussion, they walked away ignoring him.
- Goodbye and Good Riddance (first appearance)
Arnold shares his first name with Arnold Perlstein from The Magic School Bus series, who also has glasses and orange hair.
- He has a blog about the alien sightings, much like Jimmy Jones.