Jodah, the Unifier

Legendary creatures you control get +X/+X, where X is the number of legendary creatures you control.
Whenever you cast a legendary spell from your hand, exile cards from the top of your library until you exile a legendary nonland card with lesser mana value. You may cast that card without paying its mana cost. Put the rest on the bottom of your library in a random order.

Obelisk of Alara

{1}{W}, {T}: You gain 5 life.
{1}{U}, {T}: Draw a card, then discard a card.
{1}{B}, {T}: Target creature gets -2/-2 until end of turn.
{1}{R}, {T}: Obelisk of Alara deals 3 damage to target player or planeswalker.
{1}{G}, {T}: Target creature gets +4/+4 until end of turn.