Captain Blue is shaped like a sea sponge, contrary to his nephew, SpongeBob, who is shaped like a kitchen sponge. Blue has holes all over his body and is light orange. He has a few yellow teeth left, wears a blue cap and brown pants, and has a gray beard.
Captain Blue is very lazy, but it is probably because he is retired. He enjoys drinking Clam Tomato Chowder Juice, listening to country music on his old record player, and talking on a CB radio.
He was born to Grandma and Grandpa SquarePants. Blue has two known brothers: Harold SquarePants and Sherm SquarePants, as well as possible other siblings.