That's former Vice President of NFL officiating Mike Pereira taking a jab at Gruden's color commentating abilities. If you still can't put a face to Pereira, he's that guy that pops up on FOX many times when a play is challenged and offers his opinion about the challenged play and makes small talk with the announcers covering the game. I think he's a pretty solid addition to the telecasts as he offers another opinion on a controversial play other than the alternative of Joe Buck rambling for minutes uninterrupted without football as a distraction.
Anyways, twitter beef is one of my all-time guilty pleasures. It's especially great when it's two somewhat famous people taking potshots 140 keyboard mashes at a time for the public to see. Sadly, it does not look like Gruden has a twitter account as I have my doubts this one is him, so if he offers a retort it will not be 140 characters of rage coming back @MikePereira.
Since the internet is yet to develop a sarcasm font, I think it's fair to accept this as being the literal way he watches the telecasts on Monday night. Hopefully as he is muting Gruden and unmuting Tirico a couple hundred times a game he is not confusing Jaws with Gruden and missing out on his wonderful pearls of wisdom.