Gamera/Nightmare Fuel


 * Gamera 3: Revenge Of Irys is chock full of these. In particular, the scene where Gamera is fighting against several Gyaos and pretty much just destroys the area with no regard for human life (except for one child he deliberately saves from a Gyaos). The people who survive the ordeal aren't grateful that Gamera stopped the Gyaos, they're terrified that they were nearly killed.
 * The mortally-wounded Gyaos screeching in pain as its on the ground before Gamera roasts it alive. One of its eyes is hanging from the socket.
 * Or how about when Gamera blasts a Gyaos out of the sky and it explodes sending molten chunks of burning Gyaos-flesh raining down on unsuspecting civilians.
 * Irys. To elaborate, imaging a creature that starts off as an Ugly Cute tentacled...thing with a shell, but quickly grows into an Eldritch Abomination. To make things worse, it is a Complete Monster that feeds by impaling you with its tentacles and draining you of your body fluids. And, it tries twice to absorb a little girl so it can consume her and become strong enough to kill Gamera.