Unpopular opinion coming up…
T-1000 (on a side note, not the Genisys version, nor any of the “liquid metal over endoskeleton” versions).
The original T-1000, played by Robert Patrick in T2.
The original Terminator, T-800, actually wasn’t scary that much. Sure, Arnold Schwarzenegger fit into the Terminator’s role perfectly, but the original Terminator had several characteristics that made him more of an “juggernaut” version of an assassin robot. His inability to socialize and his awkward accent (yes, I know that’s not Arnold’s fault) made him stand out.
Then the T-1000 came along. He was everything the T-800 was, but so much more as well. He was able to assimilate into the humans perfectly, communicating with the other humans more than the T-800 had ever done. He kept his police officer attire, which made his job so much more easier.
The T-800 might have been nearly indestructible, and tried to complete its mission to the end, but the T-1000 can do it as well. Whatever you throw at it, it reforms, and no door is going to stop it. You can only slow it down.
It’s able to disguise itself as will- which was actually legitimately surprising when I first saw the film.
In the end, the T-1000 is so much more effective at doing its job than the T-800, due to its various array of abilities. All the T-1000 can do makes it so much scarier for me.
Also, this scene is legit one of my top 5 scariest scenes of all time.
The way that Robert Patrick runs- expressionless and his arms wheeling- is really frightening.