Green Dragon, Overseer of the Damned, and Warstorm Surge

Prerequisites

• Green Dragon in hand
• Overseer of the Damned on the battlefield
• Warstorm Surge on the battlefield
• available

Steps

1. Cast Green Dragon by paying
2. Green Dragon enters the battlefield, triggering itself and Warstorm Surge
3. Resolve the Green Dragon trigger, causing any creature your opponent control that are dealt damage this turn to be destroyed
4. Resolve the Warstorm Surge trigger, dealing damage equal to Green Dragon's power to any creature an opponent controls
5. Green Dragon triggers, destroying the creature dealt damage
6. The creature dies, triggering Overseer of the Damned's second ability, creating a 2/2 Zombie creature token
7. The Zombie enters the battlefield, triggering Warstorm Surge, dealing damage equal to the Zombie's power to any creature an opponent controls
8. Repeat from step 5

Results

• Destroy all nontoken creatures opponents control
• Near-infinite creature tokens
• Near-infinite ETB