Dennis the Rabbit

Dennis, named "Mr. Cutie Patootie" by Candace (first seen in No More Bunny Business ), is a rabbit and a former agent of the O.W.C.A. who went rogue and attempted to hack into the mainframe of the organization. Major Monogram tells Agent P that he is a master of disguise, showing several images of Dennis that are sinister, followed by his harmless "mindless animal" look.

History
In order to gain access to the Flynn-Fletcher household he lets Candace see him. She immediately attempted to adopt him. Candace used him as a living doll for dress-up and taught him tricks, inadvertently showing his obsession with carrots. Linda spots Perry and Dennis battling, but on her double-take, sees both posing as mindless animals. She seems unconcerned that Candace has adopted a pet without her consent. He was defeated by Agent P, whose lair he had infiltrated to do so, and likely taken into captivity ("No More Bunny Business").

Background Information

 * Like many rabbits, Dennis has a strong fondness for carrots, and has even interrupted his mission in order to eat carrots, which eventually led to his capture. He eats so many carrots he cannot fight back when Agent P hand-cuffs him.
 * Dennis growls as his only vocalization, reminiscent of Agent P's own chatter.
 * Carl dresses up as him whilst he tries on disguises ("Undercover Carl").
 * It could be that he is an allusion to Alec Trevelyan from the James Bond movie Goldeneye.
 * He does not like pink like Perry.
 * He also has a "mindless-pet mode" like Perry as a secret agent.