Oskar, Rubbish Reclaimer

Oskar der Aktenretter (Oskar, Rubbish Reclaimer) (de)

Legendary Creature - Human Wizard | Power/Toughness: 3 / 3 (CMC 5)
This spell costs less to cast for each different mana value among cards in your graveyard.
Whenever you discard a nonland card, you may cast it from your graveyard.