Mermaid Man used to be a regular old guy, until he went out fishing one day. He saw a mermaid out in the distance and thought, 'That outfit would look great on me!' His new outfit appalled everyone so much that they threw him in the ocean. His fat body made him sink down to Bikini Bottom. He can breathe underwater now.
A popular theory is that Mermaid Man's multiple chins formed into gills, allowing him to breathe.
- "Merman Maid away!!! Oh wait..."
- "Where's my bra?"
- "I secretly want to make out with Barnacle Boy."