Hello, hello, hello! I work at the brazilian localization group and I decided to share some big plot related information with you people:

- UB are not catchable except for UB-0Z (Zero Zeta);

- UB aren't aliens or from another dimension. They come from the future. They are human/pokémon hybrids.
In the future, science evolved to the point human and pokémon can crossbreed.

- By the end of the game, you will be offered the option to MARRY one of your Pokémon (max friendship needed).
When you use the S&M version of pokémon-amie on your pokémon husband/wife, the background changes to a comfy bedroom and the pokémon will moan and its face gets red when you pet it, very cute.

- In the post-game, it will trigger an event where UB-0Z comes from the future. It is your child!

- UB-0Z can have 18 different forms depending on its typing. The typing will be Dragon + the primary type of its pokémon parent.

- If you don't marry a pokémon/marry a pokémon the same sex as your character, the 0Z event will not happen :(

- I don't really know how to draw, so I can't sketch 0Z formes, but I attached a rough sketch I did of Mallow so you can be sure I am saying the truth.