Veinwitch Coven + Carnival of Souls + Thunder of Unity

Veinwitch Coven

Carnival of Souls

Thunder of Unity

How it works

1. Cast the creature card from your hand for 0. The creature enters, then immediately dies as a state-based action due to having 0 toughness.
2. When the creature enters, Carnival of Souls and Thunder of Unity trigger.
3. Resolve the Carnival of Souls ability, adding and losing 1 life.
4. Resolve the Thunder of Unity ability, gaining 1 life and causing each opponent to lose 1 life.
5. When you gain life, Veinwitch Coven triggers, causing you to pay to return the creature card from your graveyard to your hand.
6. Repeat.