“Craziest” could mean pretty much whatever you want it to. Good, bad, intricate, simple or whatever. As long as the moment you saw it you knew you wouldn’t forget it. I knew a guy at my old job who holds this place for me. Giant white dude and his white wife dressed as Puerto Ricans. It was crazy racist/stereotypical. Added context, this was 2 years ago.
Back in college, a couples costume made of trash bags. I’m not sure exactly what it was meant to be but the crazy part is only trash bags
I’ve heard of Halloween parties where people wear cheap tank tops & what not and then via various games other people can cut away at the fabric, removing pieces until the inevitable orgy
Which is all fun and good for them, maybe they occurred once or twice for people in my orbit but I heard about them all the damn time. People were very proud of the fact that they were having sex.