Counterpoint

If the target spell has X generic mana in its mana cost, use the value chosen for X when determining that spell’s mana value.

If a spell you cast has X generic mana in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.

You cast the card from your graveyard as Counterpoint resolves. You can’t wait to cast it later in the turn. Timing restrictions based on the card’s types are ignored.