He is an ordinary-looking skunk who wears an air helmet like Sandy does. He has black eyes, gray eyelids, a black nose, and black and white fur.
Role in episode
Plankton tries to use Mr. Stinky to prevent customers from going to the Krusty Krab. The reason he sprays his huge spray of stink is because Plankton puts a bee into Mr. Stinky's air helmet. The customers think that he was a cat, but when he sprays the Krusty Krab, all of the customers, Squidward, SpongeBob, and Mr. Krabs frantically leave the restaurany due to the stink.
Plankton uses Stinky as a distraction so he can steal the Krabby Patty secret formula, but he cannot because there are several safes. Mr. Stinky is removed from the restaurant by the HAZMAT Unit and sent away back up to the surface in a basket lifted up by balloons, only for the little number of said balloons to bring him back down toward Bikini Bottom, causing the people to run away.