Marvel Iron Man

If you believe the stories, NIMROD is a mutant-hunting Sentinel from the future.

In actuality, NIMROD is a secret US Government-run operation, created and operated to deal with not only a subterranean threat (fabled Cobra-La) but also possible Alien presence recently discovered on Earth (possibly from the Lunartixx Galaxy.) The NIMROD Sentinels (of which, this is just one model - a prototype proof-of-concept,) are deployed to stop the threats as they emerge.