Squidward Tentacles - He dresses up as the restaurant's mascot, SpongeBob. He gives out autographs and cooks the food, while having difficulties. He also operates the Fun Train for Horace A. Whopper at the end of the episode.
SpongeBob SquarePants - He drives the The Krusty Sponge Fun Train for the customers, which ends up being exhausting for him. He is also mistaken as a guy in a SpongeBob costume by one customer when she says "That's the worst SpongeBob costume I've ever seen" when he got too exhausted to work.
Mr. Krabs is arrested by an agent for selling the Spongy Patties that poison anyone who consumes them, turning them yellow with green spots, making them resemble SpongeBob. The case is the entire community of Bikini Bottom against Eugene H. Krabs, who knows he cannot win the lawsuit. Before the judge makes his final decision, Krabs makes him change his mind when he realizes the judge is a fan of SpongeBob. The restaurant goes back to normal, and Squidward takes the judge for a ride on Krusty Sponge Fun Train.
Inspiration and changes
Inspired by a critic's impressing comments on a television review, Mr. Krabs decides to make the Krusty Krab SpongeBob-themed and names it the "Krusty Sponge." Changes include a sign with a sponge wearing a Krusty Krab Employee Hat that says "The Krusty Sponge" in red letters. Outside the restaurant is a fun train which SpongeBob pedals constantly without a break. Inside, Squidward is dressed in a SpongeBob suit and is put on grill duty despite the fact that the suit did not allow his arms to move, which caused him to accidentally slap a little boy.
Due to the poisoned patties called "Spongy Patties" (which, in reality, were expired Krabby Patties), many customers start a trial against Mr. Krabs. The patties turn everyone yellow with olive green holes, like SpongeBob. The trial is near an end when Mr. Krabs makes the judge change his mind by allowing him to have unlimited rides on the Fun Train, with Squidward driving it.
This is first time Mr. Krabs changes the name of the Krusty Krab without dropping the "Krusty" part. The second time was in the episode "Krusty Dogs" where he renamed it the "Krusty Dogs."