Mine would be the Scott Prince one in 2001. Back when the NRL had their Name-A-Game VHS thing, i'd get the Channel 9 games usually. That's how i saw it. I covered my eyes when Nine showed the replay, it was that bad.
Remember watching the news clip on that day when John Farragher got severely injured. Is he still on the door at Panthers?The one Josh Mansour received from a flying knee-cocked Anthony Don. Obviously not as bad as Farragher or McKinnon long term but perhaps just as traumatic.