When I was growing up we had a kid who's dad was a mailman. This guy was well known through the neighborhood as a scarcastic-smart***-prankster. They lived by the school (K-8).
One October a couple of weeks before Halloween, they put a scarecrow out on their porch dressed up in the typical flannel shirt, jeans, gloves, hat...etc...etc...sitting on a lawn chair. The kids walking by the house would see it on a regular basis before that Halloween and got used to the decorations.
Yeah, so on Halloween night the kid's dad switched places with the scarecrow - clothes and all. Jumped up to offer the kids candy when they came on the property. Scared the bejesus out of the trick-or-treaters. Actually heard that some parents got really angry/upset at it. Scared the parents, too I think!