Malcolm, Keen-Eyed Navigator, Lightning-Rig Crew, and Umbral Mantle

Prerequisites

• Malcolm, Keen-Eyed Navigator on the battlefield
• Lightning-Rig Crew on the battlefield
• Umbral Mantle on the battlefield
• Umbral Mantle attached to Lightning-Rig Crew
• Lightning-Rig Crew does not have summoning sickness
• You have at least three opponents

Steps

1. Activate Lightning-Rig Crew by tapping it, dealing 1 damage to each opponent
2. Malcolm triggers, creating a Treasure artifact token for each opponent dealt damage this way
3. Activate three Treasures by tapping and sacrificing them, adding
4. Activate Lightning-Rig Crew by paying and untapping it, giving it +2/+2 until end of turn
5. Repeat until you have two or less opponents remaining

Results

• Near-infinite damage to all other opponents
• Infinite damage to target opponent
• Near-infinitely large Lightning-Rig Crew until end of turn