I wonder if anyone has heard the theory of whether or not Gastly is a dead Cloyster or something to that effect.
I mean... Cloyster's core does look eerily similar to Gastly! :o
I doubt it'll leave the ocean when it dies, I sure as heck wouldn't leave my favourite place.
I've always been into Gen 3 theories since I got Sapphire as a child and I would watch those scam videos about the closed door in Mossdeep or the White Rock. Ditto being a failed Mew clone makes a lot of sense to me as well.