Mikaeus, the Unhallowed + Morselhoarder + Yahenni, Undying Partisan

Mikaeus, the Unhallowed

Morselhoarder

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing Morselhoarder.
2. When Morselhoarder dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect.
3. Resolve the Yahenni ability
4. Repeat.

This elegant loop turns Morselhoarder into an infinite mana and sacrifice engine, anchored entirely by Mikaeus, the Unhallowed and his passive undying anthem. Because Morselhoarder enters with two -1/-1 counters that naturally cancel out any +1/+1 counter it receives, it can endlessly die and return via undying without ever permanently accumulating counters to block the trigger. With Mikaeus keeping the cycle going, Yahenni, Undying Partisan acts as the willing executioner to continuously sacrifice Morselhoarder, allowing you to filter its native mana-producing ability into infinite colored mana while racking up an arbitrarily large number of death and sacrifice triggers.