B.H.I.

The victim (let's call him Ian, for argument's sake, it was always an Ian) would be asked "Do you have a BHI?"

A positive reply would be met with the ear-splitting declaration "Ian has a baldy half-incher!"

Negative replies would be met with the slightly less offensive "What, so you don't have a big hairy invader?" On the whole, we preferred the positive response.