Google+ Auto Awesome - Photobomb Feature

So I'm familiar with several auto awesome features (the snow, best smile, animations...) but I just can't explain this one.

I was just watching Top Gun (that Verge article about Top Gun 2 got me way more excited than it should have) and snapped a couple of pictures of my TV during the movie (volleyball scene, of course...) to send to some friends, whatever.

A few minutes later I get a notification that "2 Auto Awesome pictures have been added", so I open them up and I really have no explanation for these...

Img_20140401_214441-aprilfools_medium

via lh3.googleusercontent.com

Img_20140401_214410-aprilfools_medium

via lh4.googleusercontent.com

Obviously the actual pictures I took are the same without that guy in front.

Who is that guy and why ?