Retreat to Emeria, Haru, Hidden Talent, and Dromar's Cavern

Prerequisites

• Retreat to Emeria on the battlefield
• Haru, Hidden Talent on the battlefield
• Dromar's Cavern in hand

Steps

1. Play Dromar's Cavern
2. When Dromar's Cavern enters, it and Retreat to Emeria trigger
3. Resolve the Retreat to Emeria trigger, creating a 1/1 Kor Ally creature token
4. When the Kor Ally enters, Haru triggers, earthbending Dromar's Cavern
5. Resolve the Dromar's Cavern trigger from step 2, causing you to sacrifice it Haru triggers, returning Dromar's Cavern from your graveyard to the battlefield
6. Repeat from step 2

Results

• Infinite ETB
• Infinite lifegain triggers
• Infinite lifegain
• Infinite creature tokens
• Infinite landfall triggers