Purple Smoke Flare

The Purple Smoke Flare item is a pyrotechnic device used primarily to mark a location by placing a purple smoke column object on the terrain.

Some uses that people have come up with:
 * marking locations for raids
 * smoke bomb the Flag Rooms in the Warsong Gulch battleground
 * props for floor shows and fashion shows

Source
This item is crafted with Engineering (335); taught by Schematic: Purple Smoke Flare, a world drop.