Mega MIGHT work if balanced carefully. Like, it gets a different ability that's a sidegrade to Shadow Tag and slightly different stats. Or maybe be a super offensive anti-Wob.
But not an evolution. Eviolite Wob would be scary, and it's a Pokemon that's on the fine line between OP and UP already. Whatever it evolves into would be a beast, and it's existence would make Wob too good.
On 12/02/12 I said I wouldn't change this until something impossible happened. Now, Earthbound just got re-released in the US.