Source: Fizban's Treasury of Dragons

Weapon (any bow), Rare (Requires Attunement)

The limb tips of this magic bow are shaped like a dragon’s wings, and the weapon is infused with the essence of a chromatic, gem, or metallic dragon’s breath. When you hit with an attack roll using this magic bow, the target takes an extra 1d6 damage of the same type as the breath infused in the bow—acid, cold, fire, force, lightning, necrotic, poison, psychic, radiant, or thunder.

If you load no ammunition in the weapon, it produces its own, automatically creating one piece of magic ammunition when you pull back the string. The ammunition created by the bow vanishes the instant after it hits or misses a target.