That theory's actually pretty interesting. I've never thought of it that way before.
Sorry to be the bearer of bad news, but all of you are wrong. The truth, as always, is much more simple.
Think about it.
Cubone's face is the only part that we NEVER see, and Diglett's face is the only part we EVER see.
They're both Ground-types.
Have you ever seen the both of them in the same room at the same time?
I watched someone on youtube and it's true that cubone or marowak were going to evolve into kangaskan but the people who were making it abandoned it. But, they didnt delete the data of the evolution entirely hence creating Missingno. They had to put Missingno somewhere because it's data wasnt fully deleted so they put it next to cinibar island. And i dont why it only happens when u talk to the old man that teaches u how to catch pokemon.
There are a few problems with this theory. One: the baby Kangaskhan doesn't look at all like a Cubone, other than them both being small, dinosaur-like creatures.
They are different colors, their hands and feet are different, Cubone has spikes coming out of its back and the eyes are completely different. Also, if you look at the adult Kangaskhan's head, Cubone's skull doesn't look like it belongs to a Kangaskhan. (The skull has horns, while Kangaskhan has ears.) Though it is slightly different, Cubone's skull does look very much like Marowak's head.
And there's also the case of the mother Marowak ghost defending her Cubone child, which would prove that Marowak are the parents of Cubone, not Kangaskhan. So no, I don't think Cubone are baby Kangaskhan. There's not really anything official to suggest it.
Apparently they were supposed to evolve into Kangaskhan, And thats why MissingNo often evolves into a Kangaskhan. That theory was abandoned though, Because in the 1st generation, there was not split evos nor evos with more than 2 pokemon on them. I just think its a really messed up theory that is a dead end :l
Just a Game Freak screw up. And why would Marowak die anyway D:
I don't get where this theory comes from honestly, Kangaskhan doesn't even look like Cubone, plus we've all seen Baby Kangaskhan and know that it is the same species as it's mother. It's a weird theory but I don't think there is much to back it up, it's more likely that Cubone is wearing something like a Marowak's skull, though it doesn't look exactly like that so who knows. Cubone isn't really supposed to be shown without it's skull, it's supposed to be part of the Pokemon and it's design.
I have to agree with Aquanova here. It is a interesting theory but they look similar in very few ways. 1: colors are different. 2: Cubone has spikes on it's back. 3: The Skull Cubone wears is different then a Kangaskhan's skull. 4: Eyes are different. and Finally 5: They are different types.
And that is all :)
I don't think this theory works either, I really can't see many similarities between Cubone and Kangaskhan. I think it's a really creative idea though.
M' evolves into Kangaskhan, Missingno doesn't evolve at all. Anyway, M' evolving into Kangaskhan is due to a quirk of index numbers and nothing else (Kangaskhan being the very second Pokémon programmed into the game, after Rhydon).
I never really understood the "Cubone is Kangaskhan" theory, personally. Apart from the prior-mentioned fact that they look nothing alike, Cubone is a tiny 1 foot tall thing while Kangaskhan is a 7 foot tall beast. Cubone's skull mask is only slightly larger than its actual head, whereas you could probably fit the entirety of Cubone's body into a Kangaskhan's massive skull.
I will say though, I am very much supportive of the idea of them making the baby Kangaskhan into its own Pokémon. To this day I'm still utterly flabbergasted that they missed such an excellent opportunity when baby Pokémon were introduced in Gen II.
Also, just for fun, in case you ever wanted a better idea of what Cubone looks like under there, check out the infamous card showing the art of a fairly decent portion of Cubone's face. Not surprisingly, he looks pretty generic.
They could have changed the colour pallette of the Pokemon. Any changes could have been done before release, if these weren't too complicated. And even if the Pokemon arn't alike, there's still evo-lines looking even more strange in Gen 1. I don't think we'll ever find any proof for this parent theory. Only Game Freak knows the truth. But I wonder why Garoora is the only Normal-Type Pokemon Sakaki uses (in Green Version). Lack of good Ground-Types or did they plan to have Garoora as Ground-Type?
True, I see what your saying. But I'd say it's impossible for them to be alike. And speaking of Missingno, has anyone here caught it?
I never really believed this theory, though I always found it amusing. Sure, there are similarities between the sprites, but you shouldn't use the old, Gen 1 sprites that don't have much detail to compare. In the newer art, there are little similarities.