I was running a game for some of my comrades, including Aaron. For anyone who is a regular listener, you'll know that Aaron is a Colossal do-gooder. I don't think he's actually capable of playing an evil character. He always wants to do the right thing, and avoids pointless violence like it was herpes. He truly wants to subdue the villain, no matter how evil or ruthless, and turn them over to the authorities.
Which makes what happened even more delicious.
It was a dimensional-hopping game, in which the players were on a pirate ship being attacked by a battleship-sized ironclad vessel, complete with primitive torpedo launchers. Aaron sees that they are about to launch one of the torpedoes via a catapult. He is playing a guy in an Iron Man powersuit, so he fires a pulse blast at the torpedo, hoping to prevent the launch. What he didn't know was that right below the catapult were twenty other torpedoes ready to be launched. I make a single fate roll, and the following takes place. The torpedo detonates, setting off all the others. The other ship is torn in half by the massive explosion, killing most of the three hundred men on board instantly. Aaron, the consumate nice guy, literally watches in muted horror as hundreds of bodies are thrown into the air, most of them flying apart from the explosion. Aaron's RL expression is complete shock.
And then, all of the pirates on the ship they were protecting rush over and start congratulating him, slapping him on the back and singing his praises for destroying the enemy ship. Aaron doesn't say a word, realizing he just killed hundreds with a single shot. And finally, as his character stands in silent agony over the deed he just committed, surrounded by a crew of non-human pirates cheering his name, I decided it would be a good exclamtion point to the whole event to have a single severed hand fall from the sky and bounce off the front of his suit's face plate.
An asshole thing to do? Maybe. But the rest of the group loved it. And Aaron resisted going into a combat situation in-game for the next few sessions. It seems to fly in the face of gamer logic, but the hell with it. I loved it.