Penalty challenged.

I think that if scoring, change of possession and yardage markers marking are all challengable, then they need to add 1 penalty challenge per game. This could be for a call or non call. Each HC could throw out a blue flag to have the play in question reviewed. He would explain what he thinks he saw and the refs would look at the replays and enforce the finding. You would also get one for OT.
The Rams could've challenged the face mask call. The Saints obviously would have challenged the non PI call. Now here's the rub. When do you do your P challenge? The Rams could've jumped on the first of the non play lock at zero violations and would've had it erased. But, then they couldn't challenge the face mask play later. The refs are wrong a lot and miss blatant holds, illegal blocks, catches and such so you need to pick the right wrong call. What amazes me is how are fern they make mistakes. But, with the new P penalty blue flag, at least each HC can try to fix one call which could be the game changer. Thoughts?