Seconding 7 and 8 above.
Also:
- Satanists (probably at your local schools)
- razorblades and drugs in your Halloween candy
- poltergeists
(Okay, maybe I'm it yearning for spooky season a little.)
to make this a bit more unpleasant, but it was true:
AIDS.
Many extremely terrifying ads on AIDS, coupled with actual teachers assuring us that none of us were gay but nonetheless don't, like, do anything that you could catch it. You all saw that horrendous TV movie death we just watched, right?