Vilifus, the Unwasteful

At the start of your main phase, if you control at least three rats, each opponent discards a card.
•If an opponent discards a land card, add {b} to your mana pool.
•If an opponent discards a creature card, create a 1/! black Rat creature token with deathtouch.
•If an opponent discards a noncreature, nonland card, return target rat from your graveyard to your hand.