Cathars' Crusade + Aerie Ouphes

Prerequisites

• An additional creature with flying and indestructible on the battlefield.

Steps

1. 1Activate Aerie Ouphes' ability by sacrificing itself to deal 4 damage to the creature with flying and indestructible.
2. 2Aerie Ouphes's Persist ability triggers, returning Aerie Ouphes from your graveyard to the battlefield with a -1/-1 counter on it.
3. 3Cathars' Crusade triggers, putting a +1/+1 counter on all creatures you control.
4. 4The -1/-1 counter and +1/+1 counter on Aerie Ouphes are removed as a state-based action.
5. 5Repeat.

Effects

• Infinite +1/+1 counters on most creatures you control
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers