List of Doofenshmirtz's pets

Throughout the series, Heinz Doofenshmirtz was seen to have many pets, from his childhood to his adult life.

Pigeons
The Pigeons were brainwashed so that they would dump their fecal waste on Roger Doofenshmirtz at his award ceremony. However, Perry escaped and turned the pigeons against Heinz. ("Tree to Get Ready")

Susan and Susan
Susan and Susan were two crocodiles owned by Heinz Doofenshmirtz in "The Ballad of Badbeard" to which he'd tried to feed Perry. He claims to have named them after each other.

Bobo the Rabbit
Bobo the Rabbit is the rabbit that Heinz Doofenshmirtz used in his magic act when he was in 7th grade.

History
During a 7th grade magic act, Doofenshmirtz was unable to pull Bobo out of his hat, but instead accidentally pulled out a skunk. Heinz had since been searching for the rabbit, until one struggle with Perry the Platypus when the platypus used a tophat to launch it at him. ("Leave the Busting to Us!")

Mr. Cat
Mr. Fluffypants was the name Heinz Doofenshmirtz gave to a cat he found on the street. Heinz named the cat "Mr. Fluffypants" because he was fluffy and looked as if he was wearing pants. Doofenshmirtz also remarked that the cat resembled his uncle Fluffy Pants, whose name was ironic for the fact that he wore no pants.

The cat caused unrelenting havoc in Doofenshmirtz's lair, tearing up his old blueprints and reactivating his used -inators.

At the end of the day, the cat's real owner appears to reclaim his missing cat and calls him by his real name, "Mr. Cat". ("Spa Day")

Background Information

 * Doofenshmirtz's returning the cat to his original owner can be categorized under his random acts of kindness.
 * He was lost for five years. ("Phineas and Ferb The Movie: Across the 2nd Dimension").

Hoarfrost
He was a pet cockroach that Heinz had in his childhood back in Gimmelshtump. It was one of the few things that made him happy.

He tried to fuse a cockroach that might have been Hoarfrost or another cockroach with a cone of garlic ice cream with unfavorable results. ("Canderemy")