an armed head, a bloody child, and a crowned child

The apparitions' prophecies play a significant role in shaping Macbeth's actions and beliefs throughout the play.

They were an armed head, a bloody child, and finally a crowned  child , with a tree in his hand.They warn Macbeth to be cautious of Macduff, assure him that no man born of a woman can harm him, and predict his safety until Birnam Wood comes to Dunsinane.