Manhacks

Manhacks are small attack robots that propel themselves via two sets of counter-rotating blades. Once a manhack identifies a target, it and its brethren charge the target with their vicious allow blades, their goal to literally hack their target to death. Union batteries last a long time, but luckily the manhack's bodies are weak, taking only a few swings from a bat or pipe of some sort, or a burst from an SMG.