Master Pakku - Avatar: The Last Airbender #63

Master Pakku

Set: Avatar: The Last Airbender (TLA)
Collector Number: 63
Type: Legendary Creature — Human Advisor Ally
Rarity: Uncommon
Mana Value: 2.0

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 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.)