Master Pakku [Avatar: The Last Airbender]

Cost: 1 U Prowess (Whenever you cast a noncreature spell, this creature gets 1/ 1 uni until end of turn.)
Whenever Master Pakku becomes tapped, target player mills X cards, where X is the number of Lesson cards in your graveyard. (They put the top X cards of their library into their graveyard.)