Sentinels

The Sentinels are a group of mutant-hunting robots in the Marvel Universe. The X-Men are usually portrayed as their main opponents (except M-Series Sentinels).

Sentinels are programmed to locate mutants and capture or kill them. Though several types of Sentinels have been introduced, the typical Sentinel is three stories tall, capable of flight, projects energy blasts, and can detect mutants.