Ao, the Dawn Sky, Mortuary, and Phyrexian Metamorph

Prerequisites

• Ao, the Dawn Sky on the battlefield
• Mortuary on the battlefield
• Phyrexian Metamorph in hand
• available

Steps

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

Results

• Infinite LTB
• Infinite ETB
• Infinite death triggers