Tourach the Dark One

When Tourach the Dark One deals combat damage to a player, each opponent discards a card at random.
Whenever an opponent discards a card, put a 1/1 black Thrull creature token with, "Sacrifice this creature: Add {b} to your mana pool. Gain 1 life." onto the battlefield.
Thrulls spells you cast cost {b} less to cast.