Eternal Black Flame

With the desire to burn things in the universe the caster conjures inextinguishable flames. But it takes a toll on the caster and can go out if you lose concentration. When you cast this spell on a creature it must make a dexterity saving throw or take 6d10 fire damage. If it is cast on an area it spreads in a 15ft radius, if a creature passes through the affected area it must make a dexterity saving throw. On a failed save the creatures is ignited as if hit by the spell. In order to keep this spell active the caster can’t use any movement and use their action to keep it active. This spell is a concentration spell.