Color Identity: B

Initial Card State
- Walking Ballista in exile (exiled by Agatha's Soul Cauldron).
- Agatha's Soul Cauldron and Butcher Ghoul on the battlefield.
Notable Prerequisites
- Butcher Ghoul has at least one +1/+1 counter on it.
Steps
- Activate Butcher Ghoul using Walking Ballista's second ability by removing a +1/+1 counter from it.
- Repeat step 1 until Butcher Ghoul has no +1/+1 counters on it.
- Resolve all Butcher Ghoul abilities dealing 1 damage to Butcher Ghoul, and any remaining damage to any target(s).
- Butcher Ghoul dies as a state-based action due to having 0 toughness.
- Butcher Ghoul's undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
- Repeat.
Results
- Infinite death triggers.
- Infinite ETB.
- Infinite LTB.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).