

The episode "Mermaid Man Begins" reveals that, through a series of meticulous and intricate events, he and his friend were suddenly equipped with aquatically themed superpowers when they left the microwave on long which made it become radioactive which is what gave them their superpowers. Despite this, Mermaid Man has maintained some of his abilities as a skilled crime-fighter, though some of them have been comically shifted to reflect stereotypes commonly associated with his age however, few of his admirers seem particularly bothered by this. As opposed to his sidekick, Barnacle Boy, he is slightly less grouchy and somewhat more tolerant of SpongeBob's ecstatic optimism, but only to a certain extent as SpongeBob's slips or mistakes have triggered serious consequences before in the past, and his partner seems annoyed with Mermaid Man's absentminded tendencies. As a young adult, Mermaid Man had a muscular, athletic build, but the elderly Mermaid Man is overweight and out of shape. Mermaid Man is portrayed as a stereotypically senile elder, and appears to suffer from slight memory loss as he is easily confused by others' behavior, though this also could be partly credited to his hearing loss. "What could you possibly describe about the character that has a thing all over his nose like this. They are among the few humans who can breathe underwater and speak to the inhabitants of Bikini Bottom. Mermaid Man appears to suffer from memory loss and yells a prolonged "evil!" whenever he hears the word, while Barnacle Boy seems to be the more sensible and more irritable of the two.

Mermaid Man and Barnacle Boy are two elderly superheroes who live in a retirement home and are stars of SpongeBob and Patrick's favorite television show. Following Borgnine's death in 2012, Mermaid Man and Barnacle Boy were reduced to non-speaking roles. Mermaid Man and Barnacle Boy first appeared in the eponymous season one episode that premiered on August 21, 1999, and have since been featured as recurring characters. They were respectively voiced by guest stars Ernest Borgnine and Tim Conway, who both previously starred in the 1960s sitcom McHale's Navy. Mermaid Man and Barnacle Boy are a duo of fictional characters in the American animated television series, SpongeBob SquarePants.
