Ao, the Dawn Sky, Mortuary, and Gigantoplasm

Prerequisites

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

Steps

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

Results

• Infinite LTB
• Infinite ETB
• Infinite death triggers