If a second Elesh Norn, Grand Cenobite comes under your control, you'll put one into its owner's graveyard due to the “legend rule” at the same time that any of your opponents' creatures getting -4/-4 are put into their owner's graveyard for having 0 or less toughness.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.