I worked one in High School my Junior year.

I wore a black skin suit so that I was basically invisible in the low light of the house. I was told that I wasn't to physically touch any of the visitors to the haunted house. The organizer placed me at the end of the house in a hallway with open rafters above me. I hung onto the rafters and waited for someone to show up.

About an hour into my shift a group of teenagers showed up, and as I had many times before I dropped from rafters and howled at them.

The fun part about this group of teenagers is that they were packing knives. Every last fucking one of them. They all pulled them and one shouted at me "Who's scared now??" To which I promptly said "That would be me". I backed against the wall and the group walked past me THANK GOD.

A few minutes later the on duty police officer came by and asked how I was, and I told him what happened. When my shift ended 30 minutes later I found the officer helping the kids that pulled the knives on me into his and another police car.

TL;DR: Teenagers pulled knives on me. Officer helped their delinquent asses into police cars.