Michael Rapaport -- Flips Out Over 'Creed' Snub (Hilarious Video)

Michael Rapaport perfectly captured what all of us were feeling when someone other than Sylvester Stallone won the Best Supporting Actor award Sunday night ... "WHAT THE F**K IS GOING ON?!"

You gotta watch the video ... Rapaport goes off when Stallone was upset by someone named Mark Rylance.

"YOU MOTHER F**KERS! WHO THE F**K IS THIS?!"

Hilarious.

By the way, Sly's friend Arnold Schwarzenegger also had a message for the actor -- but there's not as much yelling and cussing.