Artwork from Metroid Prime.
A Zoomer is a species from the Metroid series, and a very common one. It's appeared in multiple different Metroid games including Metroid, Super Metroid, Metroid Prime, Metroid Zero Mission, and Metroid Prime Hunters. While presumably they originally came from Zebes, they are now found on multiple other planets. Apparently they breed rapidly, and are also a major threat - not because they have fatal attacks, but because they tend to carry multiple different diseases around including the flesh eating bacteria, which has been the cause of many deaths and ultimately extinctions of some of Zebes' species.
They, as you can see in the image to the right, they have spikes jutting out of its shell, which can prove harmful if touched. They are also able to climb up walls easily, though can be taken out with a blast or two of your weapons.
Because they have traveled (some how, probably via a Space Pirate ship that landed on Zebes) to different planets, their species is one of the very little that have survived after Zebes was destroyed, though any Zoomer that was present during the blast was killed.