The Mindskinner 
Legendary Enchantment Creature — Nightmare
The Mindskinner can't be blocked. If a source you control would deal damage to an opponent, prevent that damage and each opponent mills that many cards.
Legality
standardLEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL