IT'S A JET BIKE. IT LOOKS LIKE IT'S GOT THE FART CAN FROM A HONDA, BUT THAT'S A PULSE JET. THE GUYS WHO MADE IT ARE LOUD.
I have no clue how fast, efficient, or safe this jet-powered two-wheeler is, but I approve of its loudness.
Want to make one and put yourself in bodily danger particularly to your bones, skin, flesh, and eardrums? They made an instructional video.
(Hat tip to Milk!)