Accursed Ignition

A beam of yellow light flashes from your pointing finger, then condenses to linger at a chosen point within range as a glowing bead for the duration. When a creature you can see enters a 10 ft sphere centered on the bead or starts its turn there, the bead will attempt to burrow into the creature's nape. If the creature is in the center of the 10 ft sphere upon initial casting of this spell, the bead automatically attempts to enter. The creature must make a Constitution saving throw. The creature takes 3d6 fire damage on a failed save, or half as much on a successful save. Upon success, the bead fails to enter. Upon failure, the bead violently enters its body and the creature is branded with the Ignisbane Curse for 3 turns.

While cursed, the target takes 1d4 fire damage at the end of their turn. Upon exposure to any separate source of fire damage while cursed, the bead ignites from within and explodes for 4d8 fire damage in a 10 foot sphere centered on the afflicted creature, removing this curse (+1d8 per spell level of initial curse inflicting spell from the explosion).

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the base damage increases by 1d6 for each slot level above 2nd.