Kaya's Ghostform, Phyrexian Altar, and Trusty Retriever

Prerequisites

• Kaya's Ghostform on the battlefield
• Phyrexian Altar on the battlefield
• Trusty Retriever on the battlefield
• Kaya's Ghostform attached to Trusty Retriever

Steps

1. Activate Phyrexian Altar by sacrificing Trusty Retriever, adding
2. When Trusty Retriever dies, Kaya's Ghostform triggers, returning Trusty Retriever from your graveyard to the battlefield
3. When Trusty Retriever enters the battlefield, it triggers, returning Kaya's Ghostform from your graveyard to your hand
4. Cast Kaya's Ghostform by paying , attaching it to Trusty Retriever
5. Repeat

Results

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