Wrexial, the Risen Deep

Math is for BlockersIslandwalk, swampwalk (This creature can’t be blocked as long as defending player controls an Island or a Swamp.) Whenever Wrexial, the Risen Deep deals combat damage to a player, you may cast target instant or sorcery card from that player’s graveyard without paying its mana cost. If that spell would be put into a graveyard this turn, exile it instead.