So the idea was half inspired off black ops, but I have had the idea of a toxic fume launcher since before black ops ever came out.
A grenade that looks like the Concussion Grenade for T+T, but it is a lighter shade of green and 1 second after landing on the ground, it would emit Nova Gas which would cover a 16x16 area and slowly kill the player. The player moves slower and jumps lower.
You can also have an one-time use launcher that shoots 2 nova gas canisters. The effects would be the same, but the gas covers a 19x19 area instead of a 16x16 area.
