Within this icy flask lies the distilled essence of the northern tundra, a place of such unspeakable bitterness that none daring enough to venture into it have returned... with their lives. Once dropped upon a tile, it will freeze all nearby units and defenses for a period of time, leaving them quite vulnerable to whatever frozen hell you wish to unleash upon them.

Flash Freeze is one of the potions available within the Vein of Sloth.