The Blue Spirit

Flash, double strike
Whenever The Blue Spirit deals combat damage
to a creature, create a colorless Treasure artifact
token with "{t}, Sacrifice this artifact: Add one
mana of any color to your mana pool."
Whenever The Blue Spirit deals combat damage
to a player, you may look at the top card of that
player's library, then put it on the top or bottom
of their library.
"So, the blue spirit? I wonder who could be behind
that mask?"—Iroh