Call him the Usain Bolt of water parks -- a guy in Jamaica stuck the most amazing water slide landing ... in fact, it's almost unbelievable!

If you thought gliding over water went out of style about 2000 years ago, you gotta see what this guy pulled off. He shot out of the slide and then ... GLIDED all the way across the pool ... and popped up on his feet on solid ground!!

Dude's gone viral, which means there's gonna be a lot of disappointed -- and possibly injured -- water park goers this summer.