Servo Skull

Flying
Canticle (You may tap this creature. If you do, you
gain 1 counter of Maintenance, then trigger any
relevant Canticle effects. All counters of Maintenance
are sacrificed during your end step.) Once you have
2 or more Maintenance counters, you may put
the top card of your library into your graveyard.
Sacrifice Servo Skull: Put an artifact from your graveyard into your hand.