What did Balaam's donkey see standing in the road?

Balaam's donkey saw the angel of Yahweh standing in the road with his drawn sword in his hand.

What did Balaam's donkey do when he saw the angel of Yahweh, and what did Balaam do to his donkey?

Balaam's donkey turned off the road and went into a field; Balaam struck the donkey to turn her back to the road.