Professor Rupert Marmalade IV, is the main antagonist of Aaron Blabey's book series The Bad Guys, as well as its DreamWorks' 42nd animated film adaptation of the same name.

Professor Marmalade is an anthropomorphic guinea pig with orange fur and a neat hairstyle. He is always wearing a white suit with a green shirt and a bow tie. However, at the end of the movie when he reveals his psychopathic nature, he has unkempt hair and wears yellow clothes that resemble gold.

Marmalade is introduced in the beginning of the film as a genius innovator, a humanitarian, philanthropist, and altruist who believed in putting the interests of other over his own. It is later, revealed that this is a façade for a selfish, greedy, lying and manipulative psychopath who only cares about himself and a liar full of bad intentions. He used The Bad Guys as his alibi for his getaway and crimes and attempted to destroy the friendship between Mr. Snake and Mr. Wolf.

He is voiced by Richard Ayoade.