Headbutt is one of Silver Crow's special abilities. It requires his special guage to be full in order to use it.
Silver Crow prepares his move by getting into a battle stance and crosses his arms around his chest. Then, a neck brace appears and energy is focused into his faceplate. He has to make physical contact in order for the move to do any damage. But, if it does make contact, it appears to do a significant amount of damage towards his opponent.