Giant Demonic SpongeBob is a character who only appears in the episode "Ghoul Fools."
His appearance is similar to SpongeBob, except he is larger, has a greenish tinge and has a lower pitched voice. He acts just like the normal SpongeBob.
When Squidward is sucked into the void by Lord Poltergeist, he encounters this giant creature. In the creature's first appearance in the episode, he shows up in the void and scares Squidward. In his final appearance in the episode he appears at the Kursed Krab, working there in the void by flipping the restaurant. His head then morphs into the Flying Dutchman's head, and he starts laughing.
His voice and laughter sounds much deeper when compared to SpongeBob's tone.