Ex-heavyweight champ Shannon Briggs went toe-to-toe with Wladimir Klitschko in the most insane way -- but did it in flip flops -- and ended up landing himself in the hospital with an injured foot.
According to Shannon ... he saw Wlad eating at a restaurant in Miami, walked up to him and had the balls to start eating food right off his plate! Briggs says Wlad got pissed and poured out a glass of water on him.
Briggs slipped and fell because he was wearing flip flops ... he claims, and also because one of Wlad's boys was rushing him.
Of course Briggs has been hounding Klitschko -- earlier this week he interrupted the champ's training session, repeatedly called him a coward ... and tried to taunt him into a fight.
Briggs says he went to the emergency room with cuts on his foot and leg from broken glass ... but won't need stitches.
We've called Klitschko's camp ... no word back yet.