I didn't even know what a ballpop was until I saw this. Apparently it's a thing. The physics explanation from some internet expert while I try to replicate the trick in my bathtub. I'm kidding, my shower is way too disgusting for baths:
When homeboy hits the water he displaces an amount based on his size/weight/force of impact. Due to science, that water is only temporarily displaced and rushes back in to fill the gap with the force of many oceans. By timing it just right, all that energy acts in a coordinated fashion to launch the floating object into the sky far higher than seems reasonable.
"With the force of many oceans." I have no clue if that's accurate or not but I like the imagery. When reached for comment about the feat, Poseidon said he wants his ball back. Also, for beachgoers to stop peeing in the ocean -- that's for marine life only. Fish don't crawl on land to pee in your yard.
Keep going for the whole video.
Thanks to Allesandro, who once ballpopped a ball into orbit around the moon.