I think the one that stands out in my mind is the time they killed my beautiful, beautiful Ghost Kraken in one fell swoop. Oh, my poor Ghost Kraken…
This was the end of act 1 boss fight in my campaign. The PCs had had it pretty easy up until that point, no big challenging combat, mostly investigation and plot/character roleplay, and I wanted to set them up against something scary to let them know that the story was ramping up and give them a sense of danger.
And so Ghost Kraken was born!
The PCs were trying to free an imprisoned demigod and had been collecting shards of a mysterious crystal (which were actually pieces of the baddie Goddess’ broken heart).
They progress through the demigod’s prison until they get to the final stage: An enormous ocean guarded by a ghostly, castle-sized Kraken.
Now they didn’t actually have to kill the Kraken, just rescue a seagull that represented the demigod which would have led to a skill challenge and some prophetic visions.
But being the blood-thirsty heroes that they were, they decide to take this thing down. It doesn’t go very well for them and half of the party are down to less than 5HP a round later. I’m dropping hints left and right that maybe there’s something important they’re forgetting coughcoughSEAGULLcough.
That’s when the Paladin gets his moment of epiphany.
He grabs the Crystal Shards that they’ve collected and chucks them right into the maw of my lovely monster. Cue moment of complete panic, frantic scribbling, 20 minutes of players laughing their asses off at me and, ultimately, an explosion of calamari as the divine magic of the shards reacts against the anti-divine magic of the prison totally obliterating my big bad scary Kraken.