Captain Magma is a superhero who is only seen in the episode: Mermaid Man and Barnacle Boy V. He is part of The International Justice League of Super Acquaintances. He is probably retired and was replaced by Squidward. He has the ability to shoot lava from his head. His costume seemingly is a red jumpsuit and a volcano hat which spurts out lava. In The Bad Guy Club for Villains, there's another superhero that's possibly the same person as Captain Magma, but is called "Professor Magma" and does not speak clearly, as he only makes gargle sounds.
- Magma Spout; Lava will come out of his head if angered. Magma is triggered by the code word, "Krakatoa!!!"
"No...No, I'm not the Quickster, I'm Captain Mag..ma (in ashes)."
- Captain Magma is a parody of the Fantastic 4's Human Torch, DC's Firestorm. and Marvel's Pyro.
- In The Bad Guy Club for Villains, there is another superhero named Professor Magma who's possibly the same person as Captain Magma.
- When Captain Magma attacks, he says Krakatoa, which is the name of an Indonesian volcano in real life.