Ring of Valki

As an additional cost to cast this spell, reveal a
black card from your hand.
When Ring of Valki enters the battlefield, you get
an emblem with You may spend mana to cast
cards put into your hand with Ring of Valki as
though it is mana of any color.
{t}Discard a card. Return target card with
converted mana cost X, where X is the discarded
cards converted mana cost from any graveyard to
your hand.