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.
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.