SpongeBuck SquarePants was an old Western hero that lived in Dead Eye Gulch. He is SpongeBob's great-great-great-great-great-great-great grandfather. He sometimes hangs out at the Krusty Kantina. He rescued Dead Eye Gulch from being taken over by Dead Eye Plankton in 1870, the "Wild West period". He is best friends with Pecos Patrick. Both ancestors seem to have the characteristics of the present SpongeBob and Patrick. SpongeBuck appears in the episode Pest of the West. After the events in the episode ended, he became the Father of Bikini Bottom and founded the modern city of Bikini Bottom.
It is unclear what the names of his wife and children are, or their overall presence in the SquarePants family timeline, but it remains present that he did marry and actually had children (otherwise, SpongeBob would not exist and have his own show!)
SpongeBuck is a Sponge, and looks very similar to SpongeBob. The only major differences are that SpongeBuck has a bow-tie, a black bowler hat with a bell, a striped shirt and a pocket watch (tucked into his pocket, the chain hangs loose). SpongeBuck was fairly easy to please, and he loved to Spurskate.