As two actions, you can create this vial full of sticky webs. As an action, a creature can throw the vial at a point within 5 meters, shattering it on impact. A mass of thick, sticky webbing expands from that point. The webs fill a sphere twice as big as normal from that point for the duration. The webs are difficult terrain and lightly obscure their area.
If the webs aren’t anchored between two solid masses (such as walls or trees) or layered across a floor, wall, or ceiling, the web collapses on itself, and the concoction ends at the start of your next turn. Webs layered over a flat surface have a depth of 1 meter.
Each creature that starts its turn in the webs or that enters them during its turn must make a Reflex saving throw.
On a failed save, the creature is restrained as long as it remains in the webs or until it breaks free.
The webs are flammable. Any 1-meter cube of webs exposed to fire burns away in 1 round, dealing 2d4 fire damage to any creature that starts its turn in the fire.