hocking video shows Draymond Green violently attacking Jordan Poole, viciously punching him to the ground right in the middle of a team practice ... video obtained by TMZ Sports. Green and Poole clearly have beef ... you see them trash-talking each other, and then it turns physical. Green walks up to Poole and gets in his face. Poole pushes Green away with 2 hands to the chest. Green, who is 6'6" and 230 lbs, responds with a vicious right cross to the face ... so ferocious, it knocks Poole to the ground and it may have knocked him out cold.