Key-per, or Gate Key-per, makes his first appearance in Adventure Time in the episode The Enchiridion! and in our fanart Adventure Time Key-per in Pajamas Sticker. His hat shaped like a key is, in fact, the key that opens the gate to Mount Cragdor, which means the Key-per himself must be inserted into the lock. He is short and tubby with yellow skin and wears a red robe which is his pajamas.