I recently saw “Rampage” from 2009. Its basically a movie where a spree shooter is portrayed as the good guy/anti-hero. Several parts gave me that pit in your stomach, teeth gritting uncomfortable moment. I really hated it. Although I’m not surprised there are sequals I am disappointed and will not be watching them.
Threads - UK based movie from 1984 which is a speculative fictional account of what would happen in the event of a nuclear war.
That’s a tough one to get though. Check out “When the Wind Blows” for an animated take on the same topic. It’s equally as bleak for different reasons.
Want some dread from an animated movie? Watership Down, especially the original, was nightmare fuel in my wife’s childhood.
That final scene of her face after giving birth.
That’s my pick as well