Color Identity: B

Initial Card State
- Activated Sleeper in your graveyard.
- Cavalier of Night and Phantom Train on the battlefield.
Steps
- Activate Phantom Train by sacrificing Cavalier of Night.
- When Cavalier of Night dies, it triggers, returning Activated Sleeper from your graveyard to the battlefield as a copy of Cavalier of Night.
- When Activated Sleeper enters the battlefield, its first triggered ability from Cavalier of Night triggers; choose not to sacrifice a creature.
- Resolve the Phantom Train ability from step 1.
- Activate Phantom Train by sacrificing Activated Sleeper.
- When Activated Sleeper dies, its last ability from Cavalier of Night triggers, returning itself from your graveyard to the battlefield as a copy of Cavalier of Night.
- When Activated Sleeper enters the battlefield, it triggers; choose not to sacrifice a creature.
- Resolve the Phantom Train ability from step 5.
- Repeat from step 5.
Results
- Infinite LTB.
- Infinite ETB.
- Infinite sacrifice triggers.
- Infinite death triggers.
- Infinite +1/+1 counters on a creature.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).