Intrusion

When I'm huddling under the covers at 4 am, scared to set foot off the bed, which happens from time to time, it's not blood and gore I'm thinking of.

No, it's that when I step onto the floor, something will reach out from under the bed and wrap itself around my foot. Something tentacular.

Or that something will creep in the window, as in this case. Something sinister invading your supposedly safe bedroom is one of the scariest things there is, in my opinion.