Prince Callous was Patrick Star, Gary the Snail, Ed Star, and Sam Star's great granduncle.
He was light blue. His scleras were green with black pupils. He wore a light blue shirt, white belt, gold belt buckle, dark blue pants, and a round, blue hat.
He was one of two children, and only son, of King Amoeba and Queen Mildew.
When he was an adult, he married Prince Dingus.
Either he or Prince Dingus had, with a female, Carl.
He only appears in "Rule of Dumb" on the family tree.