Secondary Lifter

Usually used in groups of two or three. Has advanced intelligence and fires in rapid bursts. ---In-game description

The Secondary Lifter is a lightly armored, yet craft foe which becomes common in the Mars levels onward. It is capable of both close and long range attacks. Because it is never found by itself, it will try to catch you off guard and will back away when fired at making it more harder to destroy. While not very threatening by itself, it adds to difficult fights when accompanying other robots.