Puff-N-Sting

V. Within the game of Team Fortress 2: to ignite someone on fire (usually the degreaser, (modified car parts that somehow made a flamethrower)) and swap to a flare gun, effectively rendering the receiver dead or heavily injured.

Puff-N-Sting was even better before a slight nerf of the degreaser, but still is an effective method of deleting someone's life.