Dornier D0-24 Seaplane landing OOPS!!

It was a bit more than that.
The hull was compromised and the the airplane nearly sank.
The ONLY thing that kept the airplane from flipping over was the fact it had hull mounted sponsons instead of tip floats like a Goose or Widgeon.
If it'd had tip floats it would torn the left one off and the airplane would have rolled over and sunk.
That's not just my opinion, but that of several other flying boat pilots that have watched the video.
In short the pilot screwed the pooch, his touchdown attitude was too flat which in turn lead to his "stunt".

Iren Dornier has done this maneuver before (a fast step turn on landing), but this time the bow was too deep and it went wrong.

If you watch the rudders you see full left rudder applied when the ground loop begins. Done on purpose?

Looks similar to riding on "The Scrambler" at the fall fair.

They didn't hit anything but the water at the wrong attitude.
A classic Bow Low Upset where the front of the bow gets deeper in the water than the step.

Title gives it away, "Stunt"..... full rudder, fully intended. The bow went deep, but the props never touched the water and it was just an "OH, look at me" landing.