The Sinister Slug is a villain of Mermaid Man and Barnacle Boy.
In "Mermaid Man and Barnacle Boy II", he has red eyes, and resembles a green worm. He also has very sharp teeth.
In "The Bad Guy Club for Villains", he has a bulbous beige body, completely red eyes, a few tufts and even sharper teeth. He also doesn't wear any kind of clothes this time.
|| I can turn into a skyscraper!
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