One of the most adorable Disney characters ever created is also a character whose true name we never find out. Little Boo stole the hearts of everyone who watched Monsters, Inc.
The cute toddler instantly takes a liking to her monster friends who give her the name "Boo" since they have no idea what her real name is. The audience truly becomes invested in Boo's safety when it is threatened by Randall Boggs.
Luckily, little Boo is saved and apparently gets to spend time with her friend Sully who she calls "Kitty".