Deep Cheep

Deep-Cheeps are a special variety of Cheep-Cheeps that are found in New Super Mario Bros. and New Super Mario Bros. Wii. They act and appear to be regular Cheep-Cheeps, except for the fact that these creatures are green and will actively hunt Mario or Luigi down in the underwater levels by chasing them depending on the direction they swim. Deep-Cheeps will only give up the pursuit if Mario or Luigi swim a good length away from them.

Trivia

 * Deep-Cheeps have the same color scheme as the Mr. Kipper enemy in Super Mario RPG: Legend of the Seven Stars.