Michael Phelps is known to spin some Eminem in his pre-race playlist. Perhaps that's what he was listening to Monday when cameras caught him glaring at his rival, South African swimmer Chad Le Clos, as the two prepared for a qualifier in Rio.
RELATED: Michael Phelps put personal struggles behind him and will carry the U.S. flag at the Olympics opening ceremony
Phelps has said he listens to a combination of Eminem, Young Jeezy, and Eric Church to get his mind right before races.
Maybe he was "losing himself" in the music and the moment when Phelps shot a deadly look at Le Clos as he shadowboxed while Phelps sat.
Watch the video here.
The #phelpsface photo set the internet ablaze with a plethora of memes and jokes about the look.
It looks like that mean mug is part of Phelps' DNA; his son, Boomer, has inherited it, too.
[getty src="587556244" width="574" height="594"]
In 2012, Le Clos handed Phelps his first international loss in a decade. Despite that defeat, the two were cordial enough outside of the pool to go on a shark cage diving trip in 2013.
RELATED: Why is Michael Phelps covered in purple circles? We've got the answer
The two face off Tuesday night in the 200M butterfly.
Enjoy all things sports?
Don't miss a story! Sign up for daily stories delivered to your inbox.