Bloodsoaked Insight // Sanguine Morass (Modern Horizons 3 252) - Uncommon Magic: The Gathering Card

This spell costs less to cast for each 1 life your opponents have lost this turn.
Target opponent exiles the top three cards of their library. Until the end of your next turn, you may play those cards. If you cast a spell this way, mana of any type can be spent to cast it.