Bert is character that only appears in the episode "Porous Pockets." He is friends with Harold and Harold usually lends money from him. He calls Harold, "Bill" for unknown reasons. However, he was only called Harold in a television advertisement and Bill may be his real name. He is seen in SpongeBob's short-lived mansion. Bert always needs to borrow money from Harold. In the episode "Hello Bikini Bottom!," he is a customer of the Electronics Outhouse.
He is lavender, with sunglasses and a goatee, he also wears a yellow shirt as a pedestrian. He has orange pants. He has a blue back fin. His hand fins have two darkened lines compared to the rest of the body.