Irgbul, Forgotten Origin

Devoid

Mutate {b/g}{g/u}{c}

The first time you cast a non-human creature spell on each of your turns, that spell targets this creature as if it had been cast with mutate.

Whenever this creature mutates, mill X, where X is the number of times this creature has mutated. Then you may put any number of creatures milled this way into your hand.