Infinite creature LTBInfinite creature ETBInfinite creature sacrifice triggersInfinite death triggersInfinitely large creature until end of turn
How it works
Activate Fallen Ideal by sacrificing the persist or undying creature.
When the creature dies, its persist or undying ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter or a +1/+1 counter on it due to Solemnity.
Resolve the Fallen Ideal ability, giving the creature it is attached to +2/+1 until end of turn.