Gerhard Fishtrap is an alter-ego of Squidward, who only appears in the episode "Sold!"
He is a turquoise octopus who wears brown overalls, a yellow shirt, a mustache that is made out of a broom, and a dark brown hat with a pink feather attached to it.
When Squidward hears SpongeBob knocking at his door, waiting for someone to answer, Squidward quickly puts on supplies from his closet and puts them on, then answers the door for SpongeBob. SpongeBob invites himself in, and waits for dinner while Squidward goes into Patrick's house, then changes. He was never seen after that.