Halloween Quandary

So I was thinking about female Halloween costumes recently (in general, not for myself) and I've noticed a large percent of them consist of taking a profession, outfit, regular costume, animal etc. and adding "slutty" or "sexy" in front of it. To wit:

Usual suspects like "Sexy Cowgirl"





















"Sexy Nurse"























and "Sexy Pirate"























as well as "Sexy Harry Potter" abound.
















But, what doesn't work under this formula? So far I've come up with: Sexy Grandma, Sexy Morbidly Obese Woman, Sexy Sumo Wrestler, and Sexy Exposed Chest Wound Victim (but I'm sure there are some sickos out there for each). Any other thoughts?

Oh, and I went out and got my Ali G costume instead of simply recycling my J.D. from Scrubs outfit and calling myself Dr. McDreamy. Pictures are coming.