stop (dead) in (one's) tracks
To stop at the exact spot where one is and hold motionless. We stopped dead in our tracks when we heard rustling in the bushes just off the trail. The kids were running along the lawn when the sound of a loud motorcycle stopped them in their tracks.
stop one (or something) dead in one's (or something's) tracks
Fig. to stop someone or something suddenly and completely. The gunshot stopped the killer dead in her tracks. The arrow stopped the deer dead in its tracks.