Even though Dr. Doofenshmirtz is Perry’s nemesis when Perry isn’t trying to stop Doofenshmirtz from doing evil the two are actually friends. In the Season One episode Oil on Candace, Perry tries to cheer up Dr. Doofenshmirtz when he can’t convince his Professor that he’s good at being evil. In the episode Dude, We’re Getting the Band Back Together, Perry helps Doofenshmirtz throw a birthday party for his daughter Vanessa. In the episode Put that Putter Away, Perry and Doof vacation together. In one episode, Perry pretends to be Doofenshmirtz’s pet so that Doof can impress a woman he wants to date. In the episode It’s About Time, Perry has a song about how sad he is without Doofenshmirtz after Doof replaced him as an enemy with Peter the Panda. At one point, Dr. Doofenshmirtz tells Perry “You are my rock, Perry the Platypus, by which I mean the one person who’s always there for me”.