Mary's Mother is an extremely old deaf woman. She appears in the episode "Chocolate With Nuts" when SpongeBob and Patrick sell her chocolate. She lives with her elderly daughter Mary in Bikini Bottom, but she herself is ancient compared to just about anyone in the city, including her daughter. She is shriveled up to the point where she appears to be merely a head and a spine, and thus must get around by a wheelchair. She's extremely hard at hearing and has no physical eyes left. She is also somewhat bad-tempered and impatient, often irritating her daughter Mary to no end.
When SpongeBob and Patrick come to Mary's doorstep, her mother comes forth to see what they are selling. Mary is forced to scream at the top of her lungs that they are selling chocolate bars, to which her mother reminisces on when chocolate was invented, and how much she hated it. Patrick then tells her that the chocolate will make her live forever if she rubs it on her skin. Excited at this offer, she buys a bar from the boys, much to her daughter's dismay, and demands that Mary start rubbing her with the chocolate.
Later in the episode, Mary and her mother double-date Patrick and SpongeBob at Fancy! after they become successful at selling their chocolate.