Fufel and Perr

Doofenshmirtz was a villainous inventor whose inventions only worked once and then broke. He was mostly stopped by Perry, who was too clever a platypus among the spies, and prevented Doofenshmirtz from doing anything harmful to anyone. But sometimes they would simply sit in Doofenshmirtz's tower and talk, or Perry would listen to him talk about his inventions. Their relationship wasn't strained, as is usually the case between a hero and a villain; rather, it was friendly and understanding. Doofenshmirtz became so accustomed to the platypus visiting him every day that he even began to wait for him, and instead of discussing his evil plans, they simply chatted heart-to-heart. Without realizing it, Doofenshmirtz became attached to Perry, as the platypus was the only thing that somehow relieved the inventor's loneliness.

One day, Doofenshmirtz, as usual, invented yet another machine that could transform animals into humans and vice versa. Why he created this, Doofenshmirtz himself wasn't entirely sure; he simply enjoyed inventing things, knowing in advance that his latest creation would break anyway, which no longer even bothered him. That day, Perry arrived at his tower while Doofenshmirtz was out. This had happened before, but extremely rarely. Deciding to wait for him, Perry was calmly pacing around his now-familiar apartment and, completely by accident, tripped on a wire and fell right into the beam of the new invention, which immediately activated and then, as always, broke. As soon as Perry opened his eyes, he realized he had literally become human. Red hair, human features, spy clothes over which he threw a turquoise coat. And it was at that moment that Doofenshmirtz returned home, immediately freezing in the doorway upon seeing the unfamiliar man standing before him.
Doofenshmirtz: "Excuse me, but what are you doing in my apartment?..."