Turiel, the Agent Master

+2: Sacrifice a creature, return target creature from a graveyard to the battlefield under your control, it becomes a black Phyrexian creature.
0: Target creature becomes a Sleeper Agent in addition to it's other types with "Pay 5 life: sacrifice this creature"
-10: Gain control of all Sleeper Agents, they gain haste and deathtouch until end of turn and become black Phyrexian creatures.