If there was ever a time we wanted to say 'Shut Up and Take My Money!' it would be for this, but it turns out it's not for sale. Some dude just built it for fun. It's like inventing the wheel then saying 'I got no interest in selling these wheels I just built them for fun.'.
Maybe it was weighed down incorrectly or maybe nature is just that crazy. All we know is that being on the slide while it's rolling down the beach is probably more fun than being on the slide normally.