dead in or an animal's tracks
dead in (someone's or something's) tracks
In the exact spot or instant in which someone or something is. The phrase refers to instantly stopping and remaining motionless, silent, and/or inactive upon encountering something. The sound of leaking water stopped me dead in my tracks, and I cringed at the thought of yet another home repair. Even though we were talking quietly, the noise stopped the deer dead in its tracks.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
dead in someone's or an animal's tracks
Fig. exactly where someone or something is at the moment; at this instant. (This does not usually have anything to do with death. The phrase is often used with stop.) Her unkind words stopped me dead in my tracks. When I heard the rattlesnake, I stopped dead in my tracks.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.