One last person frightened into solving:
39 heidi
Ok, close enough to deadline, I'm releasing the hounds, well the solution at least....
Once again I seem to have underestimated the difficulty, or perhaps just expected too much of a leap at the end.
The desired path to the meta answer was:
Recognize there were 5 "scary" things in the puzzle. I don't know about you, but:
13A Scary role for Karloff = MUMMY. As a kid that movies scared me to bits
33A Thriller with Sigourney = ALIEN. That movie STILL scares me, as does any chest pressure after watching it
37A Ominous bird = RAVEN. I still think that poem is spine tingling
42. Like the "X-Files" = EERIE. Nuff said
63A. My friend dressed as a ghost to try to ___ me = SPOOK. People jumping out at me, even if NOT dressed as a ghost, scare me
Put those all together and do the old "First letter" thing and you get MARES. Wait, what MARES? Horses can be imposing but not really universally scary. Ah but wait, what is the title, "Things that go bump in the NIGHT", a phrase often used to describe the scary things in life lends its NIGHT to the meta and we get NIGHTMARES, which too much Halloween can certainly give you. Good lateral thinking to those who answered DIABETES, ULCERS, LITTER, etc. but to all those who got NIGHTMARES from (or over) this puzzle; Thank You!