Mikaeus, the Unhallowed + Kithkin Spellduster + Carrion Feeder

Mikaeus, the Unhallowed

Kithkin Spellduster

Carrion Feeder

How it works

1. Activate Carrion Feeder by sacrificing Kithkin Spellduster.
2. When Kithkin Spellduster dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Carrion Feeder ability.
4. Activate Carrion Feeder by sacrificing Kithkin Spellduster.
5. When Kithkin Spellduster dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Resolve the Carrion Feeder ability.
7. Repeat.