Nearly five years after the release of The Legend of Zelda: Breath of the Wild, players are still figuring out how to do stuff that they weren't really meant to do, with the help of the game's surprisingly robust physics mechanics.
We already knew about the usefulness of Octo Balloons — a material dropped from Octoroks — which can be used to make things temporarily float. Attach them to bombs, then use the Korok Leaf to blow the bombs towards something, or attach them to rafts to create a sky-ship; or, like this player (named "Yeef" on YouTube) did, use them to make a log fly vertically.
You can then climb up to the top of the log, and as long as you have more Octo Balloons, you can just keep going up, adjusting the number of Octo Balloons to attain the height you need.
And what else would you do with a floating vertical log? Go and find bird-shaped Divine Beast, Vah Medoh, earlier than you're supposed to, of course!
Except, as Yeef says: The game developers weren't ready for this technique. After all that preparation, you'll get up to Vah Medoh, and... fall through. There's no collision detection on the bird, it seems, so it's not possible to land.
Trying to approach other Divine Beasts before you're supposed to has similar effects: Vah Ruta flings you away with a shield, Vah Naboris shoots lightning at you, Vah Rudania blows you away from the volcano (and even if you get past it, there's an invisible wall at the end), and if you try to climb the pillar in Rito Village before you're supposed to, you'll be attacked by chickens.
Perhaps the developers were ready after all, and the bird's defences are simply "cease to exist".