Hofri Ghostforge + Mistmoon Griffin + Altar of Dementia

Hofri Ghostforge

Mistmoon Griffin

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Mistmoon Griffin.
2. Mistmoon Griffin dies, triggering itself and Hofri Ghostforge.
3. Resolve the Hofri Ghostforge trigger, exiling Mistmoon Griffin from your graveyard and creating a token copy of Mistmoon Griffin that has "When this creature leaves the battlefield, return the exiled card to your graveyard".
4. Resolve the Mistmoon Griffin trigger, returning nothing from your graveyard to the battlefield.
5. Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to Mistmoon Griffin's power.
6. Activate Altar of Dementia by sacrificing the Mistmoon Griffin token.
7. The Mistmoon Griffin token dies, triggering itself twice.
8. Resolve the Mistmoon Griffin token's trigger granted by Hofri Ghostforge, returning Mistmoon Griffin from exile to your graveyard.
9. Resolve the other Mistmoon Griffin trigger, returning Mistmoon Griffin from your graveyard to the battlefield.
10. Resolve the Altar of Dementia ability from step 6, causing target player to mill cards equal to Mistmoon Griffin's power.
11. Repeat.