Ivy Lane Denizen, and Aerie Ouphes

Prerequisites

• Ivy Lane Denizen on the battlefield
• Aerie Ouphes on the battlefield
• Aeries Ouphes does not have a -1/-1 counter on it
• A creature with flying is on the battlefield

Steps

1. Activate Aerie Ouphes by sacrificing it, targeting any creature with flying
2. Aerie Ouphes' persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Aerie Ouphes enters the battlefield, triggering Ivy Lane Denizen, putting a +1/+1 counter on Aerie Ouphes
4. The +1/+1 counter and -1/-1 counter are removed as a state-based action
5. Repeat any number of times
6. Resolve all Aerie Ouphes abilities, dealing an arbitrarily high amount of damage to any number of flying creatures

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers