Petey

Petey is a male hamster who Sherman Klump tested his Youth Formula on. Though the formula initially appears to be successful with Petey acting more youthful such as having sex with a female hamster and doing backflips, he grows gigantic due to the formula being doctored with fertilizer by Buddy Love. Petey becomes aggressive, shooting poop pellets at police officers. However, he spots Dean Richmond crawling on the ground with a fur coat covering himself and is mistaken for a female. Richmond is raped by Petey on live television, which is watched by the Klumps. The event traumatizes Richmond, who fires Sherman and later is horrified when Buddy Love mentions "Jumbo the horny hamster" when confronted by Sherman and Richmond.

At the end of the film, Dean Richmond catches Denise Gaines's bouquet and notices Petey, who is now back to normal size, in a cage next to him. Petey winks at Richmond, horrifying him at first but Richmond begins to consider loving Petey.

Vocal effects provided by Frank Welker (credited as Frank W. Welker).