Altar of the Brood, Clever Impersonator, Cloudstone Curio, Strionic Resonator, and The World Spell

Prerequisites

• Altar of the Brood on the battlefield
• Clever Impersonator in hand
• Cloudstone Curio on the battlefield
• Strionic Resonator on the battlefield
• The World Spell on the battlefield
• The World Spell has exactly two lore counters on it
• You have at least one non-Saga enchantment card in hand
• available

Steps

1. At the beginning of your precombat main phase, The World Spell triggers, putting a lore counter on itself
2. The World Spell's third chapter ability triggers
3. Holding priority, activate Strionic Resonator by paying and targeting it, copying The World Spell's trigger
4. Resolve the copy of The World Spell's trigger, putting Clever Impersonator and any non-Saga enchantment onto the battlefield from your hand
5. Choose to have Clever Impersonator enter the battlefield as a copy of The World Spell, with three lore counters due to its read-ahead ability
6. Clever Impersonator triggers once, and Cloudstone Curio and Altar of the Brood each trigger twice
7. Resolve both Altar of the Brood triggers, causing each opponent to mill two cards
8. Resolve both Cloudstone Curio triggers, returning Clever Impersonator and any other non-Saga enchantment from the battlefield to your hand
9. Resolve the Clever Impersonator trigger, putting it and the non-Saga enchantment onto the battlefield from your hand
10. Repeat from step 5

Results

• Infinite mill