Boo!

A list of hoary urban legends about Halloween, bunked and debunked by Snopes, such as

Claim: Pins, needles, and razor blades have been found in trick-or-treaters' loot.
Status: True.
Origins: Unlike Trick or Treat! Halloween poisonings, many cases of tampered trick-or-treat loot involving the insertion of pins, needles, or razor blades have been documented.