I'd like to give honorable mentions to Kerry Von Erich vs. Jerry Lawler at Superclash back in the late 1980's, and Spike Dudley vs. Bam Bam Bigelow at the second ECW PPV in 1997. During the latter, I was very worried about Spike's health, and for the former I was a mark and very scared at the amount of blood coming out of Kerry.
I think that's a bunch of crap. Do you think Nash would ever be a "Superheel?" He can be a cool heel, but not a monster badass kind of heel. He gets cheered no matter what he does. Hell, most people at the arena (and at home, including me)