Bears coach John Fox just inadvertently gave the Packers the football.
Mitchell Trubisky looked to be leading Chicago on a touchdown drive to tie the game at 10-10—he found Benny Cunningham for a 23-yard completion that brought the ball to the Packers' two-yard line. The replay appeared to show Cunningham breaking the plane with the ball, so John Fox challenged the spot in an attempt to get the call switched to a touchdown.
The challenge backfired. Big time.
It turns out that Cunningham lost control of the football just before he broke the plane, and the ball went out of bounds in the end zone. The referees correctly changed the call to a fumble and a touchback, which turned a good opportunity for the Bears to score into a first down for the Packers. Had Fox not challenged the play, Chicago would have had first-and-goal at the 2.
The Bears ended up losing by a single touchdown, 23-16, so that challenge could have cost Chicago the game.