Keef was Zim's and Dib's classmate, and his only major role was in the "Bestest Friend" episode. He was planned to return in the third season but this was impossible, due to the series cancellation.

When Zim is searching for a new "best friend" Keef is the only one that qualifies and passes the tests. He later becomes a nuisance and somewhat of a creeper, causing Zim to give him a present that removes his eyeballs and replaces them with ones that shows the first thing Keef sees as Zim. That thing turns out to be a squirrel, and in the end Keef falls off a roof and explodes in an alley. He is seen in other episodes as a background character.