It won't affect my game at all, it's just something I've been curious about for a while. I don't even know if anyone knows this answer.

I've figured that some sort of RNG (random number generator) or some other kind of randomizing system is responsible for determining what color Creatu an egg will hatch into. What I'm wondering is...when does this decision happen?

Is a Creatu's color set the instant I pick up an egg? Or does it not get decided until I actually hatch that egg (which would essentially mean that hatching it today or tomorrow can make a difference in what I get, not that I'll be able to control it either way)?

But, yeah, just something random that would be interesting to know. =]