Jackie Chan Adventures

From the episode Mirror Mirror, where demons are released from a mirror and transform whoever they touch according to the person's flaw that they fear the most. Uncle calls Jackie a big-headed know-it-all, so what better manifestation for Jackie to take but a bobblehead.

Extreme Ghostbusters

In the episode Be Careful What You Wish For, a demon salesman goes around twisting people's wishes. In this instance, a naive cyclist is turned into a tree all because he wishes he could 'get in touch with his roots'.

Magic School Bus

From the episode Getting Energized, where Carlos does an Arnie impersonation, complete with physique.

X-Men: Evolution

From the episode Adrift, where Nightcrawler tests out his image inducer. Man, what a bod!

Alienators: Evolution Continues

This show is packed with mutations, particularly involving Wayne, the trainee firefighter. One of my personal favourites is in the episode Fire and Ice, where he turns into an alien, then morphs into a human snowboard.

Get Ed

There are numerous episodes of this show where Ed's (or anyone else's) suit inflates as a sort of safety mechanism. It doesn't always put them in safe circumstances, though.

Fairly Odd Parents

From the episode Odd Ball, where Timmy wishes to become a super basketball player to help the local team: