Michael Phelps is great in the pool -- we know that. But he just as deadly outside the pool as well.

Before competing in the 200-meter butterfly semifinal on Monday night, cameras caught a glimpse of Phelps seated in the aquatics center ready room as competitor and South African swimmer Chad le Clos was shadowboxing in front of him.

The glimpse showed that Phelps looked anything but pleased. And that was all the invitation the internet needed to go nuts.