A Bullette can kill an entire 2nd level party in 3 rounds. I found this out because I was DM for our next session. We rotated DM and characters were played. It was my first time as DM. I REALLY wanted to have a bullette in play, so I forced an encounter and it annihilated the group. My intent was not a TPK. I was not fully aware of the power of the combat tables and how hard it was to hit and how easy it was for it to hit back. We all called a do over and I did not DM for a long time after that.
A TPK where I was a player. My brother, Robert, was the DM. Brett and I were the players. There were just the two of us. We were in a desert campaign and headed to a canyon with a cave that was ten or twenty feet off the ground. There was some sort of treasure there. Prior to setting out, we learned of a vendor at Abdul’s (Abdul’s is another story.), that had semi-automatic crossbows that could fire several shots a round. It was based on the Chinese crossbow. Some orcs were in the area and spotted us. We figured we would be OK in the cave, but there were like 20 orcs to the two of us. We became lunch because we used swords instead of the crossbows that could unload several shots per round.
I think the first time I player Traveler we either had a TPK or a near TPK. the guy who ran the game loved Traveler, but was not a good GM.