Felidar Guardian + Altar of the Brood + Spark Double
Produces: Infinite ETB, Infinite LTB, Infinite mill



- Color identity
- WU
- Mana
- {3}{U}
Steps
- Cast Spark Double by paying {3}{U}.
- Spark Double enters the battlefield as a copy of Felidar Guardian, triggering Altar of the Brood and itself.
- Resolve the Altar of the Brood trigger, causing each opponent to mill a card.
- Resolve the Spark Double's trigger, blinking Felidar Guardian.
- Felidar Guardian enters the battlefield, triggering Altar of the Brood and itself.
- Resolve the Altar of the Brood trigger, causing each opponent to mill a card.
- Resolve the Felidar Guardian's trigger, blinking Spark Double.
- Repeat from step 2.