Poké Balls
Poké Balls are a marvelous invention, one that has made the whole of Pokémon training possible. But one must wonder - how do they work? The very idea of stuffing a giant Pokémon into a ball about the size of one's fist is so far-fetched, seemingly impossible, and yet in the Pokémon world it's the norm.
Pokémon are quite resilient, as suggested by their ability to stand up against attacks that would kill a human being in an instant. Right down to their DNA, they're extremely resilient. It is precisely this which allows Poké Balls to work. The Pokémon can be shrunk to just a few integral cells, shutting down all unnecessary functions in order to survive with such limited resources. Then, they can be rebuilt from these few cells and be pretty mcuh unchanged (there are, of course, accidents, but those are extremely rare).
The Pokémon maintain just enough cells to have all the same memories and to have some limited cognizance of what's happening outside of their Poké Balls - think of it as a computer's hard drive and internal clock. Even when the computer's off, it retains a certain amount of working ability. But if they know what's going on outside, it would follow that there would have to be other stimulus for their mind.
In Poké Balls, the Pokémon are effectively dreaming. Said dreams tend to be fairly comforting, and are linked to the type of Poké Ball - hence why certain Poké Balls are more likely to capture certain Pokémon. They feel more drawn to the dream it lures them into, because the dream is designed specifically for them.
Poké Balls originated from Apricorns, which contain a natural enzyme that breaks down a Pokémon's cells in the manner described above. This is directed by the special coating on the inside of the Apricorn into a controllable beam of 'light', which is what allows Apricorns, and later Poké Balls, to capture a specific thing. The enzyme also, upon contact with a Pokémon for the first time, codes itself to the specific DNA structure of said Pokémon, something like how white blood cells are coded to specific viruses. Hence, the Poké Ball doesn't accidentally capture the wrong thing when the Pokémon is being sent back into its Poké Ball.
The power of these Apricorns was harnessed by scientists to make a more convenient and easily made capture system, which gave rise to the Poké Ball we know today. And hence, a new era of Pokémon training came into existence, all because of a little nut and the ingenuity of the Pokémon world.
