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

Destroy all nontoken creatures opponents control

Near-infinite creature tokens

Near-infinite creature ETB

Green Dragon

Overseer of the Damned

Warstorm Surge

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

Pandemonium

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

Combos with "Green Dragon"