The Rat king, house of Rubber

{t}, Sacrifice X rat creatures: Search your library and find X creatures with defender.
{t}, Sacrifice X creatures with defender: Search your library and find X rat creatures.
Power and toughness are equal to how many rats and defenders are in your graveyard and battlefield.
"Crazy I was crazy once. They locked me in a room.
A rubber room. A rubber room with rats. And rats
make me crazy." -Unknown