Wretches

From Gears of War Realm - Gears of War Wiki Strategy Guide

These things are the Locust's war dogs. Always seen in large numbers, they have few hitpoints and can only attack in melee - but if they get close, beware. On difficulties higher than Casual a single Wretch can eat you alive if given the opportunity, and they seem a bit tougher than they should be. It should be noted that they can walk on ceilings. They can be killed with melee attacks, the chainsaw (highly effective but can leave you wide open to other Wretches) the Lancer/Hammerburst, or the Gnasher. Backing away from them and blindfiring with the Lancer can be very effective if they get close - trying to aim will slow you down too much. and these little bastards are fast.

Beware on the rare occasions when they are combined with other Locust troops - a Boomer pinning you down while Wretches surround you can be deadly.