XI, Unclean Harvester

Toxin, Undying
Sacrifice a Rat creature: Gain 1 life and put a +1/+1 counter on XI, Unclean Harvester.
XI, Unclean Harvester gets +1/-1 for each creature card in your graveyard.
"I have tasted the flesh of my clansmen, I have dined beside our demonic masters. I now see why they chose us!"