Mairsil, the Pretender + Endling + Cauldron of Souls + Blood Pet + Anger

Mairsil, the Pretender

Endling

Cauldron of Souls

Blood Pet

Anger

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 Pet'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 Endling's third ability by paying , giving Mairsil undying until end of turn.
5. Activate Mairsil using Blood Pet's ability by sacrificing it, adding .
6. When Mairsil dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
7. Repeat.

This clever loop transforms Mairsil, the Pretender into a self-sustaining engine by utilizing the cage counter mechanic to borrow activated abilities from exiled cards. While Blood Pet fuels the mana necessary to activate Endling's undying ability, Cauldron of Souls grants Mairsil persist, allowing the two counter mechanics to continuously neutralize each other upon death. Meanwhile, Anger sits quietly in the graveyard, granting hasty attacks once a Mountain is secured, ensuring this perpetual cycle of sacrifice and resurrection yields infinite black mana, death triggers, and enter-the-battlefield effects.