The head of the thing that looked like Timmy - it couldn't be Timmy, surely? Tracey couldn't bring herself to believe that the bloodied snarling came from her lovely little boy - turned to face the scream.
Half-kneeling on Rick's stomach, it's head faced Tracey.
If there was any breath left inside her, if there was any air left in the world, Tracey would have screamed again, for Timmy's eyes locked with hers and they were full of love and need. It's breathing lost it's guttural, liquid desperation and it's bloodied, dripping teeth became visible in a disturbed grin of recognition.