Sentinels (X-Men Movies)

Sentinels are the titular and main antagonists of X-Men: Days of Future Past. They are specialized mutant-hunting machines created by Dr. Bolivar Trask with help from Colonel William Stryker and HYDRA to hunt down and destroy mutants.

X-Men: Days of Future Past
In 1973, Bolivar Trask pitches the Sentinels to Congress but they decline him so he pitches them to foreign powers. Mystique attempts to kill Trask in revenge for the murders he has committed of mutants while creating the Sentinels, not knowing the future this will create, but is interrupted by Charles Xavier, Beast, Magneto and a time-traveling Wolverine who are attempting to prevent the destruction caused by the Sentinel project's completion. Unfortunately, the fight with Mystique exposes mutants to the world and President Nixon agrees to their use while Mystique's blood is collected from where she was wounded, allowing the Sentinels of the future to have her powers. Magneto, both to stop the Sentinels and to use them to take over the world, surrounds them in steel, allowing him to control the Sentinels at their unveiling on the White House lawn. Magneto uses the Sentinels to attack the crowd and hold off Wolverine, Xavier and McCoy, but before he can kill what he believes to be Nixon (really a disguised Mystique), McCoy suppresses his mutation with a serum causing a Sentinel to turn on Magneto. He quickly disables it, but the distraction allows Mystique to shoot him with a plastic gun, wounding him and then knock him out, deactivating the Sentinels. After Xavier convinces Mystique through telepathy to let Trask, Nixon and his cabinet live, the world sees that a mutant saved the President and the Sentinel program is shut down and Trask is arrested for selling military secrets to foreign powers, erasing the dystopian future.