The Mist is a 2007 horror film based on a Stephen King book. Thomas Jane stars. Wikipedia says, "an unnatural mist envelops the town and conceals vicious, Lovecraftian monsters as extreme tensions rise among the survivors."
Screenrant says, "The Mist's ending is still one of the most shocking final scenes ever featured in a movie." Empire Online says it is "is one of the best horror movies of the last few years."