While King Neptune is being mind-controlled he uses it to fry Mr. Krabs in the final level.
The SpongeBob SquarePants Movie
King Neptune uses his trident to freeze Mr. Krabs upon discovering that he allegedly stole his crown and sent it to Shell City, even though Plankton actually did it and framed Krabs for it.
Near the end of the film, upon discovering that Krabs was innocent all along, Neptune apologizes and unfreezes him.
SpongeBob accidentally picks up King Neptune's trident and takes it to the Krusty Krab. He accidentally makes dancing Krabby Patties and the customers love it, so Mr. Krabs tells him to make more. SpongeBob angers the trident while trying to make more of the dancing Krabby Patties, so it causes trouble instead of good.
Later, SpongeBob turns on the switch and the trident becomes larger and powerful. SpongeBob says he is going to help the people of Bikini Bottom with it, but he only causes trouble and chaos for them.
King Neptune later regains possession of the trident.
"Ahem. [points to switch]"
In The SpongeBob SquarePants Movie, King Neptune's trident being accidentally set to "Real Boy Ending," which is a reference to Disney's Pinocchio.