Azriel's Iron Horns (5e Equipment)
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Wondrous Item (helmet), very rare (requires attunement)
Azriel's Iron Horns grants you the ability to cast a 3rd level hex (p. 251 PHB) using the helmet as a bonus action. You can cast hex this way four times, and the helmet regains all expended uses at dawn. Your unarmed strikes with your head while wearing this helmet also deal 3d6 bludgeoning damage and knock Medium of smaller sized creatures back 5 feet upon being hit.