So a few days ago there were a Pokémon leak of an old Pokémon Gold Demo back in 1997, sprites of these oldies can be found here. Saw some sprites and this one definitely was my favorite one. It was a beta of Mantine, looked more like a flying type, but had a really cool face pattern on it's back (not shown in this picture obviously). They certainly make recent Pokémon have a lot of sense now learning about these prototype Pokémon and their typing or evolution states.

But anyways, have a beta Mantine, tried to give it an official look but color and appearance I tried to replicate as best as I can for sprites with limits to them. Hope it's good enough.