When he sees something on TV or anywhere else that looks like it is going to be scary, his reaction is to immediately cover his ears. He also is very sensitive to
loud abrupt
noises like baloons popping (he can blow a whistle for hours), or fireworks. When he was two, at a minor league baseball game, they had a fireworks display, and he was terrified, so I held my hands over his ears the whole time, but he still cried and clearly didn't like it.