King Mackerel

King Mackerel is the merman ruler of Mertropolis, and appears in The Adventures of Super Mario Bros. 3 episode The Ugly Mermaid. His daughter is Holly Mackerel.

Throughout the episode, King Mackerel worries about Bowser's threat to destroy Mertropolis, and is surprised to see that Mario is afraid of the water. At the end of the episode, after Mario saves the city, King Mackerel awards him with a medal.