Amplifire

You ignite an ally’s battle spirit, in as much a literal sense as a metaphorical one. Select one willing creature within range. For the duration of the spell, this creature has advantage on all attack rolls, and it deals an extra 1d6 fire damage with every attack. At the end of each of its turns, the creature takes fire damage equal to its level, or equal to its challenge rating if it doesn’t have one. This damage cannot be reduced in any way. At the start of the creatures turn, it can choose to end the spell (no action required). The spell also ends early if the creature starts its turn with 0 hit points.