Yggdrasil

Yggdrasil the shiny Xerneas was found and caught on Ultra Sun version.

Bit of a funny story with this one... I wasn't even intending to hunt Xerneas. I was looking for Mewtwo's wormhole at the time, found Xerneas's instead, said to myself "Ok, I'll give him five encounters and then leave." ....and then one reset later, there he was. I was floored LOL not only was he my first ever shiny legendary, he was a 2nd-encounter shiny legendary XD

Yggdrasil (C) me
Xerneas (c) Nintendo