Pod Crabs

From Mass Effect Wiki

Pod Crabs or "walkers" ( both unofficial names) are a mostly benign species of non-sentient creatures native to the planet Virmire. Standing about 6 to 7 feet in height, these massive grey flat-headed crustaceans walk on four sturdy arms, each ending in hard points possibly used to impale prey found in the shallow beaches and estuaries along the coasts.

They are weak, and can be killed in one shot; they leave no remains and explode to pulp. The pod crabs seem to be unaware of danger, and do not appear to notice if one of their kindred is shot down.