This potion contains a blue and black swirling mist within.  When throwing this potion, make a ranged weapon attack.  When a target is hit with this potion it explodes, causing a thick blueish black fog to rapidly expand in the area, filling a 15 foot cube.  Vision is obscured within this area, and you cannot see into, out of or through the smoke.  The smoke lingers in place for 30 seconds, but may be removed by a strong enough wind.