Walter Haddock is a crazy, old prospector who appears in the episode "Mustard O' Mine."
He is an elderly green fish who wears a red plaid shirt, dark blue overalls, and a light brown hat with a dark brown stripe. He has a large gray beard, bushy gray eyebrows, and a glass left eye.
Role in episode
He first appears in the Krusty Krab kitchen right before SpongeBob, Squidward, Patrick, and Mr. Krabs prepare to get more mustard from the Mustard Mines. He says that he went into the Mustard Mine, discovered that there is a mummy's curse there, and that nobody escapes alive. None of them believe him, and Patrick points out that if nobody comes back alive, then he should not still be alive. Walter says, "Or am I?" and quickly escapes the kitchen.
At first they think he had actually disappeared, but Squidward sees his foot sticking out from his hiding place in front of the kitchen door and points it out. Walter rejects his statement and quickly hides his foot.
Later, when SpongeBob strikes mustard, Walter suddenly comes. He plugs up the hole SpongeBob had made in the ground with a cork and tells them that the mummy's curse he told them is made up. He wanted to get them away from the mustard because if it was mined, the twenty million pounds of pressure against the condiment would cause it to erupt from the ground. Squidward does not believe him and thinks that Walter wants all the mustard for himself. He tells him to uncork it, but Walter raises his fists to threaten Squidward. Squidward does not want to fight him, but Walter beats him up anyways. Patrick joins the fight against Walter, and Walter pounds Patrick's head, slamming him into the mustard hole.
The mustard begins to erupt, and Walter bounces away crazily before calmly taking the escalator back up to the surface.