Niv-Mizzet, the Guildpact

Flying
Whenever you cast a multicolored spell, reveal
the top three cards of your library. You may
reveal a multicolored card from among them,
and put it into your hand. Put the rest of those
cards on the bottom of your library.
When Jace bestowed Niv-Mizzet with the powers of
the Guildpact, many took worry that Niv would favor
the Izzet in the newly unified Ravnica.