Lich's Mastery 
Legendary Enchantment
Hexproof You can't lose the game. Whenever you gain life, draw that many cards. Whenever you lose life, for each 1 life you lost, exile a permanent you control or a card from your hand or graveyard. When Lich's Mastery leaves the battlefield, you lose the game.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL