The T-Rex in Dinosaur (still makes me feel on-edge today!)
The snake in Honey I Shrunk The Audience
The entire Alien scene in the Great Movie Ride
Also I didn't dare ride TOT until I was 14 years old! Got as far as the front of the fastpass queue and bottled it up until then!
That's me. I always let someone else sit on the end where the alien was standing by the wall on the right side of the vehicle.