>>58004178
Actually had something like this happen in my pokemon hybrid one shot. Main character evolved from a dieno to a zweillos and his id pretty much took over the second head. Had it be a sort of combination of two consciousnesses and a single mind, both heads were their own seperate personalities but their brains still had a loose connection so their thoughts were each a very loud voice in the back of the other's head. Then one of their necks snaps and he can feel one of himselves slowly dying but he isn't sure which one it is. [Spoiler]He ends up immediately evolving into a Hydreigon, which forcibly fuses both brains back together due to their minds syncing up by both refusing to die.[/spoilers]