Now those were truly badass. I remember reading Batman vs. Predator, where batman first gets his ass kicked by Predator, then comes back wearing a new armor & whoops Predator's ass. That ws Epic.
Also, there was Superman vs. Aliens. Their acid blood was actually able to hurt the man of steel !
And there was other stuff like Predator clan/race wars etc. Serious badassery that unfortunately few people know about these days.