Deep-Cheep is a variant of Cheep-Cheep that first appears in New Super Mario Bros. and reappears in the sequel:
NSMB DeepCheep

A Deep-Cheep in New Super Mario Bros..

New Super Mario Bros. Wii. They are green in color and resemble their original counterpart,
NSMBW MegaCheep DeepCheep

A Mega Deep-Cheep and a Deep-Cheep.

but they will charge straight toward Mario. They will give up if Mario manages to swim safely away from them. Like Cheep-Cheep, Deep Cheeps also have a large version known as Mega Deep-Cheep. The deep cheep appears to be essentially a cheep-cheep with a green body, Not to be confuzed with the cheep-cheep's green counterpart which is very simular looking to the deep-cheep, But won't run after mario. The deep cheep appeared seemingly in all new super mario bros games until abruptly dissapearing in the newest one.