Mikaeus, the Unhallowed + Defiant Greatmaw + Ashnod's Altar

Mikaeus, the Unhallowed

Defiant Greatmaw

Ashnod's Altar

How it works

1. Activate Ashnod's Altar by sacrificing Defiant Greatmaw, adding CC
2. When Defiant Greatmaw dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. When Defiant Greatmaw enters the battlefield, its first ability triggers, putting two -1/-1 counters on it.
4. Defiant Greatmaw's second ability triggers, removing a -1/-1 counter from another creature you control.
5. Repeat.

This elegant loop relies on Mikaeus, the Unhallowed to grant undying to our other non-Human creatures, turning the graveyard into a revolving door. When you sacrifice Defiant Greatmaw to Ashnod's Altar for a pair of colorless mana, its undying ability brings it right back with a +1/+1 counter. That entry triggers the Greatmaw's own ability to place two -1/-1 counters on itself, which immediately annihilates the +1/+1 counter through state-based actions and leaves the Greatmaw ready to be sacrificed all over again.