The Master

Defender, First Strike
Whenever one or more Mutants you control
deals combat damage to a player
exile cards from the top of their library
until you exile a creature,
if its a human put it onto the battlefield face down,
its a 4/4 Mutant named Super Mutant,
if it was a non-human create a Centaur
(its a 2/2 black Mutant Horror).
The rest go to the bottom in a random order.