Geralf, the Fleshwright + Putrid Goblin + Altar of Dementia

Geralf, the Fleshwright

Putrid Goblin

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Putrid Goblin.
2. When Putrid Goblin dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Putrid Goblin enters the battlefield, Geralf's second ability triggers, putting a number of +1/+1 counters on it equal to the number of other Zombies that entered the battlefield under your cotnrol this turn.
4. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Putrid Goblin's power.
5. Repeat.

This delightfully macabre loop turns Putrid Goblin into an endless engine of mill and growth by weaponizing its persist mechanic alongside Altar of Dementia. Each time the Goblin is sacrificed to mill an opponent, it returns with a -1/-1 counter, only for Geralf, the Fleshwright to immediately counteract that penalty and steadily grow its power through successive entry triggers. Because the +1/+1 counters cancel out the -1/-1 state-based action, the Goblin can be continuously sacrificed back into the Altar to grind through an entire library card by card.