Archghoul of Thraben + Mortuary + Shambling Ghast + Altar of Dementia

Archghoul of Thraben

Mortuary

Shambling Ghast

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Shambling Ghast.
2. Mortuary, Shambling Ghast and Archghoul of Thraben trigger.
3. Resolve the Mortuary trigger, putting Shambling Ghast on top of your library.
4. Resolve the Shambling Ghast trigger, creating a Treasure token.
5. Resolve the Archghoul of Thraben trigger, revealing Shambling Ghast from the top of your library and putting it into your hand.
6. Resolve the Altar of Dementia ability, causing target player to mill a number of cards equal to Shambling Ghast's power.
7. Activate the Treasure token by tapping and sacrificing it, adding .
8. Cast Shambling Ghast by paying .
9. Repeat.