Sheoldred (MOM #125)

Menace

When Sheoldred enters, each opponent sacrifices a nontoken creature or planeswalker of their choice.

{4}{B}: Exile Sheoldred, then return it to the battlefield transformed under its owner’s control. Activate only as a sorcery and only if an opponent has eight or more cards in their graveyard.

(As this Saga enters and after your draw step, add a lore counter.)

I — For each opponent, destroy up to one target creature or planeswalker that player controls.

II — Each opponent discards three cards, then mills three cards.

III — Put all creature cards from all graveyards onto the battlefield under your control. Exile this Saga, then return it to the battlefield (front face up).