James Cameron Schwarzenegger also returned in his role as The Terminator, but this time as a protector. Unlike Schwarzenegger's character—the T-800 Terminator which is made of a metal endoskeleton—the new villain of the sequel, called the T-1000, is a more advanced Terminator made of liquid metal, and with polymorphic abilities. The T-1000 would also be much less bulky than the T-800. For the role, Cameron cast Robert Patrick, a sharp contrast to Schwarzenegger. Cameron explained, "I wanted someone who was extremely fast and agile. If the T-800 is a human Panzer tank, then the T-1000 is a Porsche." Cameron had originally wanted
T-1000 terminators. The animation was mostly similar to how it was done in "Terminator 2", only with more advanced fluid simulations. To properly depict the liquid metal being dissolved by acid, Double Negative's artists studied acid burning through aluminum, and had its final distorted forms inspired by "The Thing". In the "Terminator 2" storyline, the T-1000 is made of liquid metal. The T-800 explains that the T-1000 is a more advanced Terminator, composed entirely of a "mimetic polyalloy", rendering it capable of rapid shape shifting, near-perfect mimicry and rapid recovery from damage. Furthermore, it can use its ability to quickly liquify