It looks like an ordinary news photo until you look closely at the handshake. A mysterious "third hand" is there. Where's the body belonging to the hand? I don't see anyone who could be hiding behind Obama. It's just a disembodied hand. It's either the coolest magic trick imaginable. Or someone is up to some shenanigans with Photoshop.
Then again, maybe it's just a floating hand -- perhaps the long lost hand of Benito Juarez or Lazaro Cardenas -- or perhaps some other lost soul wanting to "lend a hand" to U.S.-Mexican relations.