Draw four cards. You lose half your life, rounded up.

At the beginning of your upkeep, target opponent may exile a card from their graveyard. If that player doesn't, you may draw a card.

All Rats have fear.
, Sacrifice a Rat: Create X 1/1 black Rat creature tokens, where X is the number of Rats you control.

Whenever a creature you control deals combat damage to a player, that player discards a card.

Rat offering (You may cast this spell any time you could cast an instant by sacrificing a Rat and paying the difference in mana costs between this and the sacrificed Rat. Mana cost includes color.)
Whenever a permanent is put into an opponent's graveyard, that player loses 1 life.