Barnacle Boy (actual name Kyle) is a 68-year old semi-retired superhero sidekick, although he still is more sane and aware than Mermaid Man. He, along with Mermaid Man, are the only real humaonids on the show. His costume is a cross between the Silver Age Aqualad and Gilligan of Gilligan's Island. Barnacle Boy also exclaims "Mumblin' Morays!" when excited. Although he turned evil and won against Mermaid Man, forcing him to give in to his demand of being called Barnacle Man, he soon reverted to being called Barnacle Boy. This was possibly because Mermaid Man could not remember to call him Barnacle Man.
Mermaid Man, his mentor, treats him as if he were a young boy, in spite him being an adult. He often calls Mermaid Man an "old coot". In true sidekick fashion he takes the brunt of the physical comedy upon himself.
