As mandated by the Equal Time Rule, I will now describe the worst Halloween costume I can recall:
We were at a smallish Halloween party at someone's house. It was the first of several stops our gaggle was making that evening. Everyone was dressed up. (I think I was Jughead.) We were all chatting and drinking. This one guy we didn't know was dressed as a flasher: a trench-coat; bare, hairy shins; socks and shoes. He walked up to our group.
"You want me to flash you?"
"Sure." We braced ourselves for some wacky over-sized phallus or similar gag.
He actually just flashed us...
Everyone laughed. A little too hard. Then people stopped laughing. Then everyone felt a little weird.
It was too authentic. It felt like his elaborate and outrageous joke was actually an elaborate and creepy ruse to expose himself to strangers without getting arrested. When his wife (yeah, she was there too) rolled her eyes and informed us that he'd done this same thing other years, our suspicion seemed all the more likely.
After a bit, we moved on to the next party.