Geemer

The Geemer is also known under the name Zoomer

A simple creature, it first appeared in the original Metroid. It is a small spiked organism that follows a very simple Artificial Intelligence algorithm. A picture is provided.

Artificial Intelligence

The AI routine is as follows: The Geemer begins by moving in either the left or right direction. When the Geemer encounters a vertical wall, it rotates by 90 degrees and walks up the wall it hit. Conversely, if the Geemer walks off of a ledge, it rotates -90 degrees and walks down the wall. This allows Geemers to move in simple circles around a complex room or object.

There is a flaw in the Geemer AI in the original Metroid. If the object the Geemer is standing on is removed, the Geemer continually spins in place, as the AI is constantly rotating by -90 degrees. This is fixed in Super Metroid, as the Geemer unceremoniously falls the floor.

In Super Metroid, a Geemer of the ordinary blue/purple type is one of the first enemies encountered. It does minimal damage. When Samus fires a Super Missile at a wall or ceiling, the resulting shockwave causes all Geemers in the area to fall off the ledge they were on.

Geemers are also seen in Metroid Prime, as three dimensional creatures resebling a turtle. They follow a very similar AI modified for three dimensional movement.

Species

There are several varieties of Geemer. There are the ordinary blue/purple ones found in Crateria, a gray type (also found in Crateria) that can only be harmed by heavy weapons like Power Bombs or the Plasma Beam, and other Geemer-like creatures which follow identical AI routines but look more like Crabs or Insects.

Oddities

There is also a unique quirk involving Geemers in Super Metroid. In Crateria, there is a small enclosed room on the right side, close to Wrecked Ship. It is visible on the map as a small rectangle surrounded by a much larger room. When Samus enters this room, a Reddish Geemer is visible above her. This Geemer follows a different pattern from normal Geemers, as it will match Samus' horizontal movements on top of the tube. This Geemer can be killed by the Wave Beam or Power Bombs, but the item dropped by it (usually energy or missiles, like any other enemy) can never be collected. Further, this particular passage can be approached from above, but when the player reaches it, the Geemer is absent. There are only hypothesis available for this intentional phenomenon, no programmer has specifically said why they put this Geemer here.