Teferi's Tutelage 
Enchantment
When this enchantment enters, draw a card, then discard a card. Whenever you draw a card, target opponent mills two cards. (They put the top two cards of their library into their graveyard.)
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL