The Flabby Patty Cook is a light purple, short, rectangular-shaped fish with light neon blue fins with dark lavender stripes and purple lips. He has five dark purple spots near the back of his head and a unibrow across his forehead. He also has white eyes with black pupils and wears an apron with grease stains along with a chef's hat and spatula. He speaks with a Southern accent.
The Flabby Patty Cook initially appeared as an unnamed fry cook. However, towards the end of the episode, it is revealed that SpongeBob created the "Flabby Patty" in an attempt to bring Mr. Krabs and Plankton closer together by making them work together to steal his formula. It is revealed that the fry cook is not a real fish, but SpongeBob in a disguise.
It is unknown how SpongeBob received the Flabby Patty Cook costume or if he made the costume.
It's also unknown how was he able to change his voice beyond recognition.