Before writing this post I was doing prep for my D&D game tonight. As part of the prep there is going to be a fight and I'm cutting off the NPCs into their part of the fight while the PCs do their part. To be ready for it - and see how much cross play their could be - I pre-rolled the fight for a couple rounds on the NPC side. Things went about as I expected, but much faster than I expected them to. Why? Because an NPC on both sides refused to stop rolling natural 20s.
This is probably my current favorite time where the dice have gone deadly. A situation where I figured the NPC vs. NPC fight would just stall out did but in a very different way. But what about you? Have any fun stories of where the dice turned deadly? Any tales of PCs being obliterated by a badguy that couldn't not roll critical strikes? Or a big, scary, bad that got nuked by a series of critical hits from an unlikely source?
As a player, my favorite deadly dice is probably in a Heavy Gear game a friend ran. The game was supposed to be desperate and gritty. Fatality was a real possibility, but that was true for both sides. Then the first fight, the dice decided they loved the PCs and hated the NPCs. A lucky shot from the PC's longest range weapon took out a big NPC vessel before it could do anything. A rain of mortar fire wiped out much of the rest of the force. In three rounds thanks entirely to way above average rolls for the PCs and well below average rolls for NPCs, the fight was over and the PCs were not only alive but almost entirely unscathed.
That the GM ran with it was impressive enough, but it reshaped the tone for the rest of the game in a large way too.
As a GM my favorite deadly dice was in a Mutants and Masterminds game. One of the PCs had invested very heavy into luck control, and decided that he'd just blow it all in trying to ruin one NPCs day that was supposed to be a terrifying big bad for the end game. I was fine with it, and it boiled down to the NPC having to roll 5 times and take the lowest roll for their attack roll. I collected the hero points, grabbed 5D20 and rolled: 20, 20, 20, 19, 19.
The PC laughed and said "well, at least it's not a crit." I shook my head and explained the NPC Crit on 19 or 20. And the fight continued. Several other times in the fight that NPC responded to unluck by doubling down on nat 20s and 19s. And the fight ended up being the kind of climactic battle you'd expect in a Super Hero epic with the fate of the universe in the balance.
How about you?