[dmurray]

They also used a practical effect for the scenes where the T-1000 needed to appear on screen at the same time as a character it had shapeshifted into.

They cast identical twins for the roles.

https://www.reddit.com/r/MovieDetails/comments/h9rzry/in_ter...

[DiabloD3]

I was expecting Linda Hamilton, but apparently more than one set of twins were in there.