For years my Halloween jam has been "Stay in, watch movies." Here's a few for tonight:

Funny Games
John Carpenter's The Thing
The Strangers
Tobe Hooper's Texas Chainsaw Massacre
(the OG, 1974, "Let's recreate a murder scene!" version, not the ill-advised sequels/ remakes)
Halloween (the OG, 1978, John Carpenter pre-Escape From LA version, not the ill-advised sequels/ remakes)

PS: Deliverance is right up in the more-disturbing-than-these-other-movies category, but that feels more like a Thanksgiving/ Christmas movie, don't you think?