Vortex Dragon

Flash, Flying
When this creature enters the battlefield, add X
mana of any one color to your mana pool.
Whenever you cast an instant, sorcery, or Dragon spell, add 2 mana of any one color to your mana
pool.
{2}{u}{r}, {t}: You may cast target instant or
sorcery spell in your graveyard this turn without
paying its mana cost. If you do, exile it instead of returning it to your graveyard.