The worst movie I’ve seen is the Poltergeist remake. If you’ve seen it you know why, but basically it boils down to a combination of toning it way the hell down and breaking the main rules of horror.

They showed the “mysterious spooky ghost world” at the end and it was basically just the house but dark and fuzzy. They also had scenes that were obviously meant as watered down replacements for scenes in the original movie. They replaced the scene where a guy peels his own face off with a scene where a drill goes through a wall