Sleepy is a fictional, anthropomorphic beige and brown tabby cat, and Rex's best friend. Despite what his name may suggest, Sleepy is very hyper and often causes trouble unintentionally for the other characters. His favourite passtime is to hang upside down from things using his large tail.
Despite what his name may imply, Sleepy is very-outgoing and quite hyper. He often causes trouble for the other characters unintentionally, including knocking over objects or setting off possible traps. He means well however, and unfortunately only his close friends and family appear to be able to tolerate him. He also seems fond of ballerinas for unknown reasons, and many other things which remind him of ballerinas such as flowers or the colours pink and purple. Sleepy also has a very active imagination, often bringing up the imaginary Planet Snegon. Due to this, he is also scared of unexistant monsters, and suffers from nightmares.