This sounds like fun- The folks at the HeatSync Labs hackerspace in Arizona recently held a Monster Mash Plushie Party:

My fantasies of becoming a surgeon were fulfilled at the recent Monster Mash Plushie Party at Arizona’s Hackerspace HeatSync Labs. Don’t let the innocent name catch you off guard, countless victim plushies were dissected, thrown in a feeder pile, and sewn back together again.

I’m pretty sure that if Hello Kitty had nightmares, this would be one of them.