How to Become a Human Again

In the game, you visit a local mystic and ask to be reverted back to human. You can throw an incendiary grenade or start a conversation with her. But really what I want is to become human again. There's also that side quest, which is to somehow plant my seeds in the ground to propagate the lemon species. So let's go to the British Museum. The museum is full of interesting items, including things like mummies from ancient Egypt. Maybe our mystic is somehow connected to that.