For me it was the face melt from Indiana Jones and the Raiders of the Lost Ark (1981).
When the Joker kills that one gangster with his electric joy buzzer in the first Batman, roasting his flesh off. It took me years before I could watch that scene again.
The scene with the horse in Neverending Story.
For me it was the face melt from Indiana Jones and the Raiders of the Lost Ark (1981).