Fain, the Broker + Intruder Alarm + Pitiless Plunderer + Goblin Bombardment

Fain, the Broker

Intruder Alarm

Pitiless Plunderer

Goblin Bombardment

How it works

1. Activate Fain's third ability by tapping it and sacrificing another artifact, creating a 2/1 Inkling creature token.
2. When the Inkling enters the battlefield, Intruder Alarm triggers, untapping all creatures.
3. Activate Goblin Bombardment by sacrificing the Inkling.
4. When the Inkling dies, Pitiless Plunderer triggers, creating a Treasure token.
5. Resolve the Goblin Bombardment ability, dealing 1 damage to any target.
6. Repeat.

This loop turns an ordinary artifact into an engine of absolute destruction, thanks to the continuous untapping power of Intruder Alarm whenever a new creature enters the battlefield. You use Fain, the Broker to sacrifice an artifact and churn out a 2/1 Inkling creature token, which immediately triggers the Alarm to untap everything. From there, you feed that Inkling to Goblin Bombardment to blast away any target, and the resulting death triggers Pitiless Plunderer to reward you with a brand-new Treasure token to keep the cycle going.