Sentinels have been programed to hunt mutants. They can detect mutant presence and identify mutants on sight. Some are equipped with stun blasts. These blast have a medium range and anyone hit by them must make a saving throw or be knocked unconscious. Once a sentinel has used this ability it must recharge it (which takes 1d6 rounds).
These mutant hunting robots could be reskinned to represent any giant robots in your Light City game