Stubborn Burrowfiend

Card text

Whenever this creature becomes saddled for the first time each turn, mill two cards, then this creature gets +X/+X until end of turn, where X is the number of creature cards in your graveyard.

Saddle 2 (Tap any number of other creatures you control with total power 2 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)