Zoomer

Zoomers are enemies found in the Metroid series. They originally appeared in the first Metroid game, but can also be found in later entries in the series. In Super Metroid, Zoomers were replaced with identical enemies known as "Geemers," but this was later clarified to say that Geemers were in fact just more powerful versions of Zoomers. Despite being a native life form of Planet Zebes, Zoomers can also be found on Tallon IV in Metroid Prime.

Behavior:

Zoomers apparently spend all of their time wandering in circles looking for food, as they lack the mental capacity to do anything else. A zoomer possesses the ability to climb both walls and ceilings at the exact same speed as they walk along the floor. While it posses a shield made of spikes on its back, a zoomer lacks a reinforced shell and is therefore very vulnerable to attack.

Zoomers lack an attack of their own, while they are dangerous to the touch they will ignore all outside threats and proceed in whatever direction they have set themselves on until killed. The only way for them to cause Samus any damage is if she directly comes into contact with one.