T-1000 played Kyle Reese in "The Terminator", in the role with the explanation that Skynet managed to acquire Reese's DNA and use it for a new Terminator. Cameron ultimately dropped this idea after deciding the audience would find it too confusing: eventually casting came down to Robert Patrick, as a deliberate contrast to the original Terminator - Cameron stated "I wanted to find someone who would be a good contrast to Arnold. If the 800 series is a kind of human Panzer tank, then the 1000 series had to be a Porsche." For a more machine-like performance, Patrick had to learn
T-1000 sequel was that both Terminators sent to the past would be T-800s like the one played by Arnold Schwarzenegger, with one being stripped down to a metal endoskeleton like the one from the original film. Once Cameron actually started working on the script, in 1990, he figured a better way was to turn the evil Terminator into a more advanced model. Cameron's original pick to play the T-1000 was rock musician Billy Idol, and storyboards had the robot resembling him, but a serious motorcycle accident prevented Idol from accepting the role. Then, he thought of casting actor Michael Biehn, who