Velis Vel Spring

When Velis Vel Sping enters the battlefield, choose a creature type.
{t}: Add one mana of any color to your mana pool. Use this mana only to cast spells or activate abilities with the chosen creature type.
{5}, {t}: Reveal your hand. You win the game if every non-land card in your hand, in your graveyard, and on the battlefield under your control are the chosen creature type.