Mermaid Man is a recurring guest character. He was voiced by Ernest Borgine and was retired after Borgnine's death. He is a semiretired hero who was brought out of retirement by Spongebob. He is shown to be a old, but wise superhero who has fought crime for 65 years. His yound ward, Barnacle Boy, has fought with him in the hit show Mermaid Man & Barnacle Boy, and the New Adventures of Mermaid Man & Barnacle Boy shot after coming out of retirement. He is shown to be nicer than Barnacle Boy, but often gets confused and lacks memory out of old age. He lives in Shady Shoals Retirement Home. He and Barnacle Boy's secret lair is the Mermalair, which is located under Shady Shoals. He has been call "Old Coot" by Barnacle Boy for the run of the series.