Requires

Twinning Staff must be on the battlefield. Heroic Intervention must be in hand. Chain of Acid must be in hand. Mana needed:

Steps

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

Results