Long, long ago we ran into some trolls and cut them in half, and the DM ruled both halves regenerated. So we cut those ones in quarters, and those all regenerated. Finally we diced them fine and when we saw they were regenerating into individual trolls again, filled the room with fire.
Time passed. We gained levels. And flying ships.
We managed to even wrangle a deal with some trollish mercenaries… the ultimate airborne shock troops: they not only did not need us to land, they did not even need parachutes, they would aim for targets on the ground.
Then one day… “Say, Eric… remember how you said trolls regenerate from even the smallest pieces?” “Uh… yeah…?”
“Alright you trollish bastards! This is the big one, the final push. We need more of you, and if you’re willing, we’ll pay every troll than lands down there, fights, and returns to the ship!”
“FIRE UP THE WOODCHIPPERS!”