The Real McCoy
{{pe})} Disappointingly, this expression does not derive from a Star Trek episode in which they cloned the starship's doctor. In fact it is a bastardisation, surviving from anonymous, over-apostrophised Glaswegian poem The De'il's Hallowe' en, which calls out "A drappie o' the real MacKay". McKay, we suppose was some kind of whiskey.
So "the real McCoy" wasn't a McCoy at all. Come in Alannis Morissette - that is ironic.