Bismack Biyombo Collapses On Bench In Scary Scene During NBA Game

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 ... he started to sway -- before he dropped into some chairs nearby.

The 31-year-old laid on the ground motionless for several seconds ... sending his teammates into a panic. Thankfully, however, he was able to get up and walk off the court under his own power -- while holding the back of his head.

It's unclear what exactly went wrong with the NBA veteran ... but OKC head coach Mark Daigneault said it looks like he's avoided a serious ailment.

"He's fine," the coach said after the game. "He just fainted, basically. He was in the locker room at halftime laughing and joking."