Ao, the Dawn Sky, Mortuary, and Evil Twin

Prerequisites

• Ao, the Dawn Sky on the battlefield
• Mortuary on the battlefield
• Evil Twin on the battlefield
• available

Steps

1. Cast Evil Twin by paying its mana cost
2. Choose to have it enter the battlefield as a copy of Ao
3. Put Evil Twin into your graveyard due to the legend rule
4. When Evil Twin dies, it and Mortuary trigger
5. Resolve the Mortuary trigger, putting Evil Twin from your graveyard onto the top of your library
6. Resolve the Evil Twin trigger, causing you to look at the top seven cards of your library and put Evil Twin onto the battlefield as a copy of Ao
7. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite death triggers