Blazing Caltrops

As an action, you can conjure flaming caltrops spread across two 5-foot-square areas within range. Any creature that enters the area must succeed on a DC 15 Dexterity saving throw or stop moving and take 1 piercing damage. Until the creature regains at least 1 hit point, its walking speed is reduced by 10 feet. A creature moving through the area at half speed doesn't need to make the saving throw. However, any creature moving through the area will take 2D4 fire damage.

At higher levels, when you cast this spell with a 2nd level spell slot or higher, add another 5-foot-square for each slot to cover with Blazing Caltrops.