Eldritch Bomb

You have joined forces with another caster who is skilled in the art of fire. Combined with your eldritch powers, you created a spell that highlights their strength and boosts your own.

To cast this spell, you need a willing caster who knows the fire bolt cantrip. This consumes a 1st level spell slot in both you and this caster. The target within range must make a charisma saving throw (DC = your save DC + other caster's charisma modifier).

On a failure, the target takes 2d10 plus your spell attack modifier in fire/force damage. For 2 rounds, the target takes your charisma modifier in fire damage and the flames can't be put out.

On a success, the target takes only half the initial damage and doesn't stay on fire.