Also, you can think of it like water polo ball. If you take a water polo ball in the water, put your hand on it and press it down, you get pressure up against it that come up.

你也可以想象成一只水球，如果你拿个水球放在水中，把手放球上向下压，你就会得到上升的反作用力。

youdao

The animals must not lie down in front of the goal or pick up the polo ball with their trunks, or the opposing team gets a free hit.

BBC: Polo-playing elephants in Nepal

Buzkashi is akin to polo, but players on horseback use a headless goat carcass instead of a ball.

NPR: Bombing Hits Sports Event In Afghanistan, 7 Killed

The ancestor of polo, this traditional game of horsemen is played with a dead goat rather than a ball.

BBC: Following the Silk Road to the end of China