Little Mikey

Little Mikey is Mike Wazowski's stuffed teddy bear which appears in Monsters, Inc. and Monsters University. Apparently, it is what is considered a bear in the Monster World.

Monsters, Inc.
In the film, it is seen on the shelf in Mike and Sulley's apartment. In its first appearance, Sulley was pushing a lot of things including the teddy bear during scaring practice with Mike. When Boo is in the house, Sulley gives it to her. In anger, Mike takes it back, because he doesn't want her germs on it. This causes Boo to cry loudly, and almost gets them caught by the CDA. Sulley tries to give it back, but Boo won't stop crying. But when she finally responds and cuddles the bear, she touches Sulley's hand, which causes it to fly away from his hands. It isn't until Mike accidentally trips into the trash can, gets a shelf full of books stuck in his mouth, and smashed by a speaker, that Boo cheers up, and starts laughing.

Monsters University
In the film's first teaser trailer, Mike's teddy bear can be seen next to him.

In the film itself, it makes a cameo on Mike's shelf in his apartment with Randall Boggs. Later on, he moves it, along with his other things, into his room with Sulley in the Oozma Kappa fraternity house.

Trivia

 * A possible version of Mike's teddy bear was seen in the Butterfly Room in Toy Story 3.
 * A teddy bear bearing a resemblance to Mike's teddy bear is seen as one of Violet's toys in The Incredibles.
 * Despite being called a "bear," the bear looks nothing like an actual bear at all, instead resembling a red monster doll with one eye, two upward-pointing horns, two clawed arms, and four tentacled legs.