Rosheen, the Eternal

{t}: Add {4} to your mana pool. Spend this mana only on costs that contain {x}.
{r}{g}{u}{b}, {t}: Target instant or sorcery card in your graveyard with {x} in its mana cost gains flashback until end of turn. Its flashback cost is equal to its mana cost.
Prior to conquering Amonkhet, Bolas realized he would need to limit the power he gave his Eternals--
Rosheen proved far too exhausting to control.