Gutmorn, Pactbound Servant

Flying, deathtouch
When Gutmorn, Pactbound Servant enters the battlefield, each player discards a nonland card.
Whenever a player discards a card during your turn, they choose another player. That player conjures a duplicate of that card into their hand. It perpetually gains "You may spend mana as though it were mana of any color to cast this spell."