The man is from the Hydraulic Press Channel.
FYFD adds some charmed explanation of the goings on:
Oobleck is probably the Internet’s favorite non-Newtonian fluid. People vibrate it, run across it,shoot it, drop it, and even use it to fix potholes. But how does oobleck hold up to a hydraulic press? Fortunately, that’s been covered, too. Oobleck is a mixture of cornstarch and water, and it’s a bit unusual in that it is a shear-thickening material. That means that the faster you try to deform it, the more it will resist that deformation. Knowing this makes the above video’s results make more sense.…
The Hydraulic Press Channel presses out other videos, of which this next one, titled “Can you fold paper more than 7 times with hydraulic press?”, is perhaps the most famous: