Enduring Renewal, Composer of Spring, and Altar of Dementia

Prerequisites

• Enduring Renewal on the battlefield
• Composer of Spring on the battlefield
• Altar of Dementia on the battlefield
• You have an enchantment creature card in hand
• You control at least six enchantments
• You have enough mana to cast the enchantment creature

Steps

1. Cast the enchantment creature by paying its mana cost
2. When the creature enters the battlefield, Composer of Spring triggers
3. Holding priority, activate Altar of Dementia by sacrificing the enchantment creature
4. When the enchantment creature dies, Enduring Renewal triggers, returning the enchantment creature to your hand from your graveyard
5. Resolve the Altar of Dementia ability from step 3, causing target player to mill cards equal to the sacrificed creature's power
6. Resolve the Composer of Spring trigger from step 2, putting the enchantment creature onto the battlefield from your hand
7. Repeat from step 2

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mill
• Infinite sacrifice triggers
• Infinite self-mill