This may be the only '80s slasher I've ever seen where there is absolutely no motive or explanation for the killer at all. We don't know who he is, we don't know why he's doing what he's doing, we don't know where he came from, we don't know a fucking thing about him.
It also doesn't help that apart from the pre-credit scene, there isn't a kill in this movie until around the 1 hour mark. They literally just needed to shoot two or three extra scenes to make this somewhat decent, but they couldn't be bothered.