Invented By: The Sentinels were originally the creation of Dr. Bolivar Trask who, despite being an anthropologist, still had enough shop training to create complex 60-foot-high living computers equipped with sophisticated sensors that could pick out a mutated gene at 200 paces. Since Trask's day, the Sentinels have been upgraded several times; the compact super-Sentinel Nimrod is the most recent and most lethal model. As tends to happen (at least in comics) when you have machines that are programmed with semi-autonomous thought, several Sentinels have achieved self-awareness and rebelled. First Appearance: Uncanny X-Men 14 What's Their Problem? The Sentinels' prime directive is to protect humanity by eliminating, or sometimes by merely containing (depends on whom is controlling them that week), the "mutant menace." Their creator feared that mutants were the next stage in an evolving humanity, and that Sentinels were the only chance non-powered humans had to survive the upcoming evolutionary change. This in spite of the fact that Trask's own son was a mutant who eventually died as the result of Sentinel action (Avengers 104). Heroes They Keep Running Into: The Sentinels at times deliberately track down the X-Men, and are at times deliberately tracked by them. They have also had tussles with other super-hero teams that include mutants such as the Avengers and Alpha Flight. During their Onslaught-induced invasion of New York, Sentinels were skragged by everyone from Spider-Ben to the Punisher to a very annoyed Dr. Doom. (Assuming that really was Doom in X-Men 56 and not one of those furshlugging Doom-bots...but I digress...) People Who Think They're Not So Bad: It's hard to tell what the public at large thinks about either Sentinels or mutants, since we the reader are only ever presented with the extremes in the debate. Being machines, the Sentinels are prone to being used by unscrupulous individuals, usually for personal and/or political gain. Being semi-autonomous, they are apparently also capable of being controlled by powerful telepaths such as Onslaught. So they do have their uses! Most Despicable Act: As mechanical beings, the Sentinels aren't necessarily responsible for what they do when people with nasty intentions control them. Having them overrun New York with the express intention of destroying all mutants and meta-humans, however, would be one of the nastier jobs they've been programmed to do.