Effects that Alter a Creature's Power/Toughness (Anthem Effects)
Initial Card State
All permanents on the battlefield (
Eirdu as Isilu, Carrier of Twilight).
Steps
If
Grim Poppet has any -1/-1 counters on it, activate it by removing a -1/-1 counter from it.
Repeat step 1 as necessary until
Grim Poppet has no -1/-1 counters on it.
Activate
Krark-Clan Ironworks by sacrificing
Grim Poppet.
When
Grim Poppet dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Repeat.
Resolve all
Grim Poppet abilities, putting infinite -1/-1 counters on any number of creatures.
Notes
The chosen anthem effect must boost toughness by at least 1 to prevent
Grim Poppet from dying due to the -1/-1 counters. You can perform this combo as a lock whenever a creature enters the battlefield to put -1/-1 counters on that creature and cause it to die.
Results
Infinite LTB.
Infinite ETB.
Infinite sacrifice triggers.
Infinite death triggers.
Infinite colorless mana.
Destroy all creatures that enter the battlefield under an opponent's control.