My Gym Partner's A Monkey

'My Gym Partner's A Monkey' is an animated series that aired on Cartoon Network between 2005 to 2008 for four seasons. Adam Lyon, a human boy, is accidentally sent to Charles Darwin Middle School, where the staff and students are all animals, and becomes friends with Jake Spidermonkey.

S3E13B: An Inconvenient Goof
Jake wears a pair of swimming trunks which expands as he dives into a flooded hallway.