In the X-Men comics, Sentinels are a type of advanced robots created to hunt and capture mutants. They were designed by Bolivar Trask, a scientist who believed that the existence of mutants posed a threat to humanity.
The Sentinels are programmed to identify mutants and capture or eliminate them. They have a wide range of capabilities, including advanced weaponry, flight, and shape-shifting abilities. Some versions of the Sentinels are even capable of adapting to the powers of the mutants they are fighting, making them a formidable opponent.