Boo

Boo is a little girl who makes friends with Mike Wazowski and Sulley in Monsters, Inc. In the movie, she was accidently released into the moster world when Sulley curiously open the door. She doesn't seemed to be scared of monster however, but the only monster she is afraid of is Randall Boggs. After going through many crazy obstacles throughtout her adventure, Mike and Sulley helped her return to the human world through her door. She even likes to call Sulley by the name "Kitty".