The deep fryer is a machine in the Krusty Krab kitchen that is primarily used to cook French fries. It first appears in the pilot episode "Help Wanted."
It is a dark gray machine with two black degree buttons on the front and fryers inside. It is located on the right side of the counter, next to the grill. Although it is almost never seen being used, it always has bubbling frying oil in it.
SpongeBob slips on a puddle and accidentally bumps Mr. Krabs into the deep fryer, frying him in the process. The two dollar bills he was playing with, Mr. and Mrs. Dollar, disintegrate from the grease.
SpongeBob tries to deep fry his feet as a means to prevent him from catching "Squid's disease." He tries his grandma's remedies of hot water followed by cold water and realizes it was actually boiling oil, then proceeding to fry his feet.