Dirty Fireworks

As part of casting this spell, you point at a creature within range before filling them with flames and volatile magic. Make a ranged spell attack, on hit grappling the target if it is your size or smaller until the start of your next turn and dealing 4d6 fire damage. At the start of the targets turn while grappled, it must succeed on a Constitution saving throw or take 3d10 force damage as it then erupts in an explosion of flame and gore. If this damage reduces a creature below 25 hit points, they explode in a shower of gore and immediately die. Allies to the initial target who witness the explosion must make a Wisdom saving throw, on failure being frightened for the next minute. This saving throw may be repeated at the start of a frightened creatures turn, ending the effect on a success.

At Higher Levels
The initial damage increases by 1d6 and the size of creature that can be grappled is increased by 1 category for each spell slot level above 4th.