Groombas are Greatures who love to RickRoll. They do have sharp fangs, but they only use them a few times in their lives. They played a big role in the Martian War, as the Groomba Empire was a leading side for a short time during the war. A few appeared in The Fakegee War but they were blown up by tanks.
They are the mostly harmless, unlike most Greatures. They're known to the Fakegees as pets.