Ezreal, Ravnica's Prodigy

When Ezreal, Prodigy of Ravnica enters the battlefield, choose a card type.
When an opponent casts a spell of that type,
you can pay {x} equal to that card's converted
mana cost. If you do, copy that spell, and counter
it. Until the end step of that turn, you may cast
the copied spell without paying its converted
mana cost.
Wizard creatures you cast cost {w}{u}{b}{r}{g} less to
cast. This effect can only discount colored mana
costs.