Sun Titan + Fiend Hunter + Altar of Dementia

Sun Titan

Fiend Hunter

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Fiend Hunter.
2. When Fiend Hunter dies, its second ability triggers, returning Sun Titan to the battlefield from exile.
3. When Sun Titan enters the battlefield, it triggers, returning Fiend Hunter from your graveyard to the battlefield.
4. When Fiend Hunter enters the battlefield, its first ability triggers, exiling Sun Titan.
5. Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to Fiend Hunter's power.
6. Repeat.