Oklahoma City Thunder center Bismack Biyombo collapsed in the middle of a game Wednesday night -- scaring the hell out of his teammates ... and the troubling scene was all captured on video.
It happened during the second quarter of OKC's tilt against the Trail Blazers in Portland ... when Biyombo was trying to lift up some Thunder players as they walked toward the bench for a timeout.
But, as you can see in the game's broadcast footage, as Biyombo was slapping some hands .