Galbatorix and Shruikan

Flying, trample, hexproof
If you would lose unspent mana, it becomes black
instead.

At the beginning of your precombat main phase,
look at the top card of your library. You may reveal
that card if it has three or more colored mana
symbols in its mana cost. If you do, add three mana
in any combination of its colors and put it into
your hand. If you don't reveal it, put it
into your hand.