 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.As a young adult, Mermaid Man had a muscular, athletic build, but the elderly Mermaid Man is obese and out of shape.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.