Michael Phelps proved ... his (mostly) naked body can be very distracting -- and he proved it by popping out of the "Curtain of Distraction" at an Arizona State hoops game Thursday night.
The "COD" is operated by ASU students to screw with opposing free throw shooters by revealing something crazy as they're about to shoot.
So, when Oregon State went to the line ... Phelps popped out in a speedo -- and the Beavers player missed BOTH of his shots.
Phelps has been training at the ASU campus -- and has essentially become an honorary Sun Devil.
BTW, Arizona State won the game in a rout ... in part due to Phelps and his distracting man junk.