Smite of Eternity

(You may cast a legendary sorcery only if you control
a legendary creature or planeswalker.)
If {b} was payed to cast Smite of Eternity, target
player discards X minus 2 cards. If {u} was spent
to cast Smite of Eternity, draw X minus 2 cards.
If {r} was spent to cast Smite of Eternity, it deals
X minus 2 damage to target player. If {w} was
spent to cast Smite of Eternity, destroy X minus
2 target creatures with toughness 4 or less.