He's a cupping hipster.
Michael Phelps has garnered a lot of attention for-- well, mostly for his swimming prowess and numerous Olympic gold medals, a tally he just won't stop adding towards. But he's also getting attention for those weird dark circles that have appeared on his back.
The circles come from a technique known as cupping, and it isn't exclusive to Phelps.
I will attest to this. Am I in one of those pictures? https://t.co/UBzhg5Fc1k
— Brian Campbell (@bcampbell_51) August 10, 2016
Apparently, Campbell's back actually is among those pictured!