Tsathoggua, Dark Whisperer

At the beginning of your upkeep, you may pay {r}{g} and sacrifice a creature. If you do, you gain 1 life and put a +1/+1 counter on each of up to two target creatures you control.
When Tsathoggua, Dark Whisperer dies or is put into exile from the battlefield, you may put it into its owner's library th