It is a light red submarine. There is a square-shaped hole on one of the walls of it for customers to order, and above it is a cover that is silver and gold in color. It has a big light blue window, and on top of the whole vehicle is a gray colored periscope.
Only one room existed in the submarine, the control room. There was enough room for a grill, the controls, and a serving window.
SpongeBob SquarePants - He drives the mobile restaurant despite not having a license and not being able to drive well.
Role in episode
Before the episode occurred, this somewhat primitive submarine was used by an unknown animal, most likely a human. Somehow, it sunk and became useless to control.
Later, SpongeBob and Patrick find its periscope sticking out of the ground, dig it up, and take possession of it. At the Krusty Krab, Mr. Krabs has the idea of "bringing the Krusty Krab to the customers." He does so by converting the submarine into a mobile restaurant.
While SpongeBob and Patrick are trying to sell Krabby Patties, Plankton attempts to use his own traveling restaurant. The duo has some unusual ways of selling the Krabby Patties; they pay the customers to eat and make a deal to get the customers to eat burnt patties (rocks).
They accidentally fall into an abyss, but they unexpectedly sell Krabby Patties and chum-wiches from Plankton's restaurant to a monster. The monster chases Plankton, as he thinks Plankton is dessert. SpongeBob attempts to get out of the abyss, but leave behind the heavy money, much to Mr. Krabs' surprise and horror. They manage to bring back several tons of colored rocks, however.
SpongeBob and Patrick's roles are somewhat reversed in this episode since SpongeBob's a good cook even though he's driving, and Patrick's a good driver even though he's cooking.