Caltrops of Charring

You infuse a set of caltrops with arcane flames and throw them up to 60 feet away. The caltrops cover the equivalent of a 15-foot radius sphere, centered on a point with range and lasting for the duration. This area shines bright light for 15 feet and dim light 30 feet beyond that.

The area is considered difficult terrain. Any creature that starts its turn in the area takes 3d6 fire damage. Any creature that ends its turn in the area must succeed on a Dexterity saving throw or take 3d6 fire damage as the caltrops flare up and ignite into a bright flame.