Paranoia is the RPG that turned RPGs on their head. Instead of co-operating, players actively try to betray, cheat and lie their way to the top of the heap.
There is an odd twist to the editions of Paranoia. There was a first edition, a second edition and a fifth edition. There was never a 3rd or 4th edition.
Given that it's a bit of a spoof on RPGs anyway, it does make sense!
Oh, and don't forget: