The Sentinels fill several fascinating roles in the X-Men franchise. They often appear as meaningless henchmen, no different from the Foot clan in Teenage Mutant Ninja Turtles or the Putty Patrollers in Power Rangers. Other X-Men stories depict the Sentinels as an apocalyptic nightmare that will inevitably end mutantkind. There's always a new Sentinel model that will escalate the threat beyond any the X-Men have previously faced. The newest upgrade in X-Men '97 is called the Prime Sentinel.