"HAVE YOU SEEN A FINGER?"
"I think everybody thought was an April Fools joke, but it was deadly serious."
That's CM Punk telling TMZ Sports what it was like to be ringside when MMA fighter Khetag Pliev has his FINGER RIPPED OFF in the middle of a match ... and it's one of the craziest stories ever!
Punk was calling the fight with his broadcast partner John Morgan at the Cage Fury Fighting Championship event in Philadelphia when the incident went down -- and says the most important thing was trying to stay focused.