Scavenger Slime

Scavenger Slime enters the battlefield with
X +1/+1 counters on it, whereas X is the
number of creatures in your graveyard.
Whenever a creature you control with one or more +1/+1 counters dies, you may pay {g}{u}. If you do, move all +1/+1 counters that were on that creature on to Scavenger Slime.
"Orzhov isn't the only guild that has a use for their patrons postmortem."