SpongeBob's Grandson is a character who only appears in "The Great Patty Caper," where he was shown seventy-five years into the future. While the episode does not reveal the relationship of the character, the relationship is confirmed in the credits.
His figure resembles SpongeBob, but he has a slightly different outfit, including a red cap. He doesn't wear a belt. He also wears a red tie that is similar to a "Kentucky bow tie" on his pants.
He was born to a son or daughter of SpongeBob and his or her spouse.
SpongeBob's grandson appears only at the end of the episode, where he is being told the story of where SpongeBob and Patrick went on a quest to find the formula (see the episode for more information). However, he is not interested in this story and cares more for his video game.