When this creature dies, you may pay {B}. If you do, target player discards a card.

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.) Other Rats you control have toxic 1. When Karumonix enters, look at the top five cards of your library. You may reveal any number of Rat cards from among them and put the revealed cards into your hand. Put the rest on the bottom of your library in a random order.

When this creature enters, choose one — • Create a 1/1 black Rat creature token with "This token can't block." • You may sacrifice another creature. If you do, scry 2, then draw a card. • Creatures you control gain menace until end of turn.

Whenever another Rat you control enters, exile up to one target card from an opponent's graveyard. At the beginning of combat on your turn, create a 1/1 black Rat creature token with "This token can't block."

Pack Rat's power and toughness are each equal to the number of Rats you control. {2}{B}, Discard a card: Create a token that's a copy of this creature.