Aether Revolt attack of the Seven Elevens

Play with the top card of your library revealed. You may play lands and cast spells from the top of your library.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.) This creature doesn't untap during your untap step. : Untap this creature. Activate only during your upkeep.

Trample When this creature enters, sacrifice it unless you sacrifice any number of creatures with total power 12 or greater.