Imagine this: a pancreas decides that the rest of the body doesn’t consist of other members of a larger community, but instead that the pancreas is the supreme organ, really the only organ that matters. All of the other organs are taking up space and energy that could better be used by the pancreas. The pancreas starts to grow, needs to grow. The growth of the pancreas is natural. This is what organs do: they grow and fight and compete, and the strongest, most fit organ survives. That’s life. And who needs an appendix anyway? And for crying out loud, there are two lungs and two kidneys. It’s incredibly selfish of the lungs and kidneys to have redundancy when the pancreas needs those wasted resources. So good, done deal.
Next it needs to replace some gray matter. Oh, you say that gray matter won’t survive outside the brain pan? Too bad, so sad; the rule of nature is adapt or die. And frankly human supremacists have shown they don’t really need their brains anyway, having already substituted ideology for perception, thought, and reasoned and/or sensible response to external conditions.
A few of the cells in the pancreas think it’s a really bad idea to kill off the body that is the pancreas’s only home. But the vast majority of the cells in the pancreas are pancreas supremacists, who either believe that God — who looks like a giant pancreas — gave them the body into which the pancreas is supposed to go forth and multiply, and over which the pancreas is supposed to have dominion; or they believe that evolution gave the pancreas the tools to make the rest of the body jump through hoops on command. Pancreas über alles.