I would assume that in many worlds they're an obscure alchemical concept. A homunculus is an artificial human that can be an attempt to copy an existing individual, but they usually have more functions than just that.

...yes, I would imagine that was the case. I'll admit, during that swarm of Ghost Pokemon I found myself reaching a bit, given how many of them I caught...

[...but he's still kicking himself for not naming any of them after Juan de Valdes Leal.]

You can't really trust Pokedex descriptions or looks to accurately describe your Pokemon's personality. I've found that one of the Pokemon I've had the most difficulty with is a small plant creature.