Requires

Tawnos, Solemn Survivor must be on the battlefield. Retreat to Coralhelm must be on the battlefield. Caged Sun must be on the battlefield. Ancient Den must be in the graveyard. Tawnos does not have summoning sickness. "White" chosen with Caged Sun. You control at least two artifact tokens. Mana needed:

Steps

1. Activate Tawnos' second ability by paying , tapping it, sacrificing two artifact tokens and exiling Ancient Den from your graveyard, causing you to create a token of Ancient Den.
2. When the Ancient Den token enters the battlefield, Retreat to Coralhelm triggers, untapping Tawnos.
3. Activate the Ancient Den token by tapping it, adding .
4. Caged Sun triggers, adding .
5. Activate Tawnos' first ability by paying and tapping it, creating a copy of the Ancient Den token and causing you to mill two cards.
6. Repeat from step 2.

Results