Xanar, Infinite Nightmare

Flying, Menace, Dread 5 (Whenever this creature attacks, each opponent puts the top 5 cards of their
library into their graveyard.)
Other Horrors you control get +1/+1 and have
Dread 2.
Creatures your opponents control that share a converted mana cost with a card in that player's graveyard can't attack or block and can't use activated abilities.