There was a book of short horror stories that I remember reading in after-school care about a million years ago. The one story I remember involves a huge mirror that lures a kid into it. At first it gives him images of a beautiful faery world, and I think he goes into it at night to explore. They get him to keep going in, though, and the last time it looks like a scene from the apocalypse in there: red sky, twisted tree branches, etc. The kid was supposed to be a human sacrifice so that these evil faery creatures could enter the real world.
There's another story that might have been in the same book, but I'm not entirely sure (I read a lot of similar stories growing up). There was a girl who was lost in the woods - camping trip, I think - and found herself running away from a large man with a lantern jaw full of razor-sharp gray teeth. She is relieved to find a cabin, only to discover that the old woman within has the same teeth.
Thanks all, for helping me relocate lost treasures from my childhood. I'll do my best to repay the favor!