Back when I was in Boy Scouts we’d see these giant inflated turds on a lake, lovingly called “The Blob”. It was the same basic concept as this, but the goal was a more vertical trajectory, and the jump onto the blob was much higher (at least to my memory it was).

One time my dad and I decided to do The Blob, and he wanted to launch me. Guest how high a 12-year old skinny kid goes when his ~250-lbs dad jumps?

After about a week I hit the murky lake water with the side of my face and swore off that cursed slug forever.

I still think it’s a really cool concept and a great lesson on physics, even for onlookers, but you won’t catch me on one of those again. At least the horizontal one in the gif is mostly contained in walls, so the trajectory is controlled. The lake one is more or less an oblong balloon sitting on the water’s surface, and the lifeguards tell the projectile generally where to lie.