Not exactly an ornament, but still spooky (and pretty funny) nonetheless.
Years ago, Dad was taking a CPR course, and the instructor advised them to take out any chewing gum prior to practicing rescue breathing on the mannequins. He said that if you practiced with gum in your mouth, it would get into the head, and then you have to take the head off and put it in the freezer so you can get the gum out. He said the only issue is that if you're going to put the head in the freezer, you have to tell your roommate in advance, as he'd once had a head in the freezer, forgot to mention it, and his poor roommate nearly had a heart attack when he went into the freezer for ice cream or something and discovered a disembodied, realistic looking head!