Mercury Smoke Grenade

Silvery Fog. You can use an action to activate and throw this item to a point within 60ft. of you. When it lands, it detonates. A thick silvery fog fills the air in a 20ft. radius sphere centered on the point of impact. The sphere spreads around corners, and its area is heavily obscured. It lasts for 1 minute or until a wind of moderate or greater speed (at least 10 miles per hour) disperses it.   A creature that starts its turn in the sphere has to make a Constitution saving throw (DC 15). A creature that is vulnerable to silver or more easily harmed by silvered weapon attacks (including vampires and lycanthropes) makes this saving throw with disadvantage. On a failed save they take 3d6 Poison damage and are Blinded. On a successful save they take half damage and are not Blinded.