Lights Outhas a terrific new movie monster. After so many horror films with familiar tropes and situations, that alone is enough to recommend it. Diana ( Alicia Vela-Bailey) is an inspired creation with a set of rules thatLights Outestablishes well and early, and even when those rules get bent a little, there’s still much fun to be had in figuring out ways around them. The best moments inLights Outare all about tweaking the audience’s expectations and fears, and because of that the scares ofLights Outare legitimately frightening and thrilling.