Mikaeus, the Unhallowed + Cauldron of Souls + Dross Scorpion + Altar of Dementia

Mikaeus, the Unhallowed

Cauldron of Souls

Dross Scorpion

Altar of Dementia

How it works

1. Activate Cauldron of Souls by tapping it, giving Dross Scorpion persist until end of turn.
2. Activate Altar of Dementia by sacrificing Dross Scorpion.
3. Dross Scorpion dies, triggering its ability, its undying ability and its persist ability.
4. Resolve the first Dross Scorpion trigger, untapping Cauldron of Souls.
5. Resolve the Dross Scorpion persist trigger, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
6. Activate Altar of Dementia by sacrificing Dross Scorpion.
7. Dross Scorpion dies, triggering its ability and its undying ability.
8. Resolve the first Dross Scorpion trigger, untapping Cauldron of Souls.
9. Resolve the second Dross Scorpion trigger, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
10. Activate Altar of Dementia by sacrificing Dross Scorpion.
11. Dross Scorpion dies, triggering its ability and its persist ability.
12. Repeat from step 4.
13. Resolve all Altar of Dementia abilities, causing any number of players to mill infinite cards.