Sorry, to clarify, it's supposed to be a multi-step process (see https://www.youtube.com/watch?v=mxlvsts3c6o ) where you get it to jump onto land, then it gets kicked to another location where you can knock it into the waterfall.

In the game, these are actually two separate entities, and I haven't done anything to prevent the "kicked" one from immediately spawning in the air here https://noclip.website/#snap/1A;ShareData=AUsPn92;%5eVT:h=19... , or to hook up the first one to the second (although the system to signal between distant pokemon, which it probably uses, is mostly implemented). There are a few other instances of things that are supposed to be spawning conditionally which aren't handled yet, like extra lapras in the beach.