Elkin Lair 
World Enchantment
At the beginning of each player's upkeep, that player exiles a card at random from their hand. The player may play that card this turn. At the beginning of the next end step, if the player hasn't played the card, they put it into their graveyard.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL