You have not read mahabharat? He is the Kalbhairab of Bhismapitamaha.
He was instructed by Krishan to be the chariot of Arjuna. Bhismapitaman dropped his bow because Shikhandi was not a man or women was inform of the chariot.

Krishna played all the roles in Mahabharat, it is his play, his changed the deskription every moment and swing as he wanted.

In one word mahabharat is about Krishna and his cunning philosophy.