I was never scared of animated characters as a child. I remember being fascinated reading stories about children who had nightmares because of Ursula.

I knew a poster on another forum who was one of those. They said they had to scroll past my posts all the time because I would often have a banner with Ursula in it and they didn't want to look at that.
I guess "Hellfire" sort of...
disturbed me when I saw it in theaters a bit, just because I didn't understand it. It's funny that my family went to church when I was young and I even had a picture version of Bible stories, but I never fully grasped God, Jesus, Hell, etc. back then. And even then it wasn't really because of Frollo so much as the jury in the red coats that appear.
Aside from that, probably Shan-Yu. "*scratching chin* How many men does it take to deliver a message?" And then he talks about returning the little girl's doll. Creepy.