If a second Night of Souls’ Betrayal comes under your control, you’ll put one into its owner’s graveyard due to the “legend rule” at the same time that any creatures getting -2/-2 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.