The T-1000 is a fictional character from the Terminator series, first appearing in 'Terminator 2: Judgment Day'. It is a highly advanced, shape-shifting android assassin sent from the future by Skynet to eliminate John Connor, the future leader of the human resistance. Made of liquid metal, the T-1000 can morph its form to impersonate others and form weapons. Its ability to recover from damage makes it a formidable adversary, posing a significant threat to the protagonists' mission.