Azelf

Flying, Vigilance.
When Azelf enters or leaves play, or attacks, exert target creature.
If you have Azelf, Mesprit, and Uxie in play, Azelf gains "{g/u}{g/u}{g/u}{g/u}: Target player shuffles target creature they control into their Library.
It is thought that Azelf, Mesprit, and Uxie all came
from the same egg.