With your cheap and cheerful HU spool, you can afford to keep a lot of different genes, so you can survive pretty much wherever you go, on whatever you find. You reproduce wildly, and spread everywhere.

However, you’re one of the smallest, weakest life forms around, because at this time, the eukaryotes, who made a few different choices, and have big, multi-layered walls, have grown up. They like eating you, like a little snack.

Wouldn’t it be nice to be big and tough like them?

Well, you might have that option; hear me out. What if you get inside one (in a failed snack attack), and lived on in there? You could be useful, acting like a little chemistry factory, making food for them? Better to feed than be food? Or better to stay on the outside, maybe get faster, or hide away?