 Other recurring characters appear throughout the series , such as SpongeBob 's ever @-@ suffering driving teacher Mrs. Puff ; Mr. Krabs ' whiney teenage whale daughter Pearl ; Plankton 's intelligent yet sarcastic computer wife Karen ; the muscular lifeguard of Goo Lagoon , Larry the Lobster ; a pirate specter known as The Flying Dutchman ; and retired superheroes Mermaid Man and Barnacle Boy , who are idolized by SpongeBob and Patrick . 
