What Happened to Peyton Manning?

Really, what happened to him yesterday? Four picks in one game? This is an player who was once regarded as the best quarterback in the league. And now he's throwing four interceptions and looking more and more like a rookie? What is he doing, channelling Colin Kaepernick? Nah, he's too cool for that...oh wait, Kaepernick always has a crappy second half...never mind. He's channelling Colin Kaepernick....that's the only explanation.