The Masque of the Red Death

At the beginning of your upkeep or whenever a creature dies, put a clang counter on The
Masque of the Red Death. Then if The Masque
of the Red Death has twelve or more counters,
destroy it and send to the graveyard every
creature with power or toughness greater than
four from the battlefield, hands, and libraries of players.
"...And Darkness and Decay and the Red Death
held illimitable dominion over all."
-Edgar Allan Poe, The Masque of the Red Death