Kelp Fries just appear in the episodes Greasy Buffoons and Kracked Krabs. They are sold at the Krusty Krab. In „Greasy Buffoons“ they are made with Krabby Patty grease. When SpongeBob wants to give them to Billy, he slips on a grease puddle and the Kelp Fries, together with a Krabby Cola and a Krabby Patty fly into Billy's face. In the episode „Kracked Krabs“, they are made out of sea potatoes.