I was working a game with a more senior official who called spearing on the running back. First time I ever seen that called on the ball carrier. The runner lowered his head and plowed into the defender who was standing straight up awaiting the runner. The senior official rationale for making the call was the runner used his helmet to intentionally punish the defender who was attempting to tackle him. Good call or bad call?

Good call, not often seen but definitely illegal as described.