Cast Heroic Intervention by paying {1}{G}, giving permanents you control hexproof and indestructible until end of turn.
Cast Chain of Acid paying {3}{G} targeting a permanent you control.
Resolve Chain of Acid, failing to destroy the indestructible permanent you control and copying Chain of Acid targeting the same permanent.
Twinning Staff triggers, copying Chain of Acid an additional time, targeting a noncreature permanent an opponent controls.
Resolve a Chain of Acid copy, destroying the permanent an opponent controls; that opponent may copy the spell but cannot target your permanents.
Repeat from step 3.

Destroy all noncreature permanents your opponents control

Infinite magecraft triggers

Twinning Staff

Heroic Intervention

Chain of Acid

Cast Heroic Intervention by paying {1}{G}, giving permanents you control hexproof and indestructible until end of turn.
Activate Hammerfist Giant by tapping it, dealing 4 damage to each creature without flying and each player.
Cacophodon triggers, untapping Hammerfist Giant.
Repeat from step 2.

Infinite damage

Cacophodon

Hammerfist Giant

Cast Heroic Intervention by paying {1}{G}, giving permanents you control hexproof and indestructible until end of turn.
Activate Krark-Clan Shaman by sacrificing an artifact, dealing 1 damage to each creature without flying.
Sonic's second ability triggers for each creature you control with haste or flash that was dealt damage, creating that many tapped Treasure tokens.
Repeat from step 2.

Infinite tapped Treasure tokens

Infinite damage to creatures

Sonic the Hedgehog

Krark-Clan Shaman

Combos with "Heroic Intervention"