Most of us wonder what Cubone's head looks like under what is supposed to be its mother's skull. However, what's rather interesting to me is that no one knows. They apparently (if what the Pokédex says is true) aren't born with them, and it would probably take a while for the baby to get the skull off the mother. That is, unless she dies immediately after she lays the egg (if they would lay eggs in real life) and thus decomposes enough to allow easy removal, but why would the baby take a skull with rotting flesh in and around it, (maybe clean it and) wear it, and take a large bone as a weapon anyway? Each species to their own, I guess....
Why hasn't anyone bred a Cubone or Marowak and looked at/photographed/videotaped the resulting baby when it hatched? Do most or all Cubone and Marowak mothers really die after the birth/laying? How do you think the tradition (I guess one could call it that) of Cubone wearing their mothers' skulls started?
I don't doubt the existence of a Marowak graveyard, but I don't quite believe that most/all Marowak (and perhaps Cubone) migrate there to get bones. Perhaps it's only the wild ones, and there is more than one Marowak graveyard. Which leaves a question: what of captive bred Cubone? Where would they get their bones from? Do people produce artificial "bones" and/or get bones from other Pokémon and animals? Do they also take from the Marowak graveyard(s)? Maybe the trainers have grown to accept the fact that their beloved Cubone/Marowak is designed to die after birth/egg-laying, let the body rot (where? In the Pokéball? In a close-by Pokémon or Marowak graveyard?), and let the baby take the skull and a bone of its choice.
And the bone weapon. I don't think it would return like a boomerang. Because of that, it would be a rather difficult thing to rely on if it missed the opponent. The Pokédex says that Marowak's bone came from another Marowak, but it's obviously much larger than any long bone in its body. Unless it came from a giant Marowak, it must have come from another creature. Cubone's more likely did come from a Marowak, though.
Other discussion welcome.
Inspired by this thread. On page two is someone's chibi manga rendition of an overskull-less Cubone. It looks like Charmander.