Dread Rage

Linger (Whenever you cast an instant or sorcery
spell, you may pay {2} and exile this card from your
graveyard. If you do, add the bracketed phrase to the
triggering spell.)
Whenever an opponent takes damage, you may
exile the top card of their library. [You may play
any number of cards other than Dread Rage that
were put into exile this turn, and you may spend
mana as though it were mana of any color to cast
those spells.]