The Howling Host

Haste, menace, persist, dethrone
At the beginning of each player's upkeep, that
player may mill 5. If they do, they gain control
of The Howling Host, untap it, and goad all
untapped creatures they don't control.
Damage dealt by The Howling Host to its owner
also causes you to lose that much life unless you
mill that many.