Mairsil, the Pretender + Carnifex Demon + Cauldron of Souls + Blood Vassal + Fervor

Mairsil, the Pretender

Carnifex Demon

Cauldron of Souls

Blood Vassal

Fervor

How it works

1. Activate Mairsil using Cauldron of Souls' ability by tapping it, giving itself persist until end of turn.
2. Activate Mairsil using Blood Vassal's ability by sacrificing it, adding .
3. When Mairsil dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
4. Activate Mairsil using Carnifex Demon's ability by paying and removing a -1/-1 counter from it, putting a -1/-1 counter on each other creature.
5. Repeat.