Archelos, Lagoon Mystic, Scaretiller, Voltaic Construct, Crystal Vein, and Viridian Longbow

Prerequisites

• Archelos, Lagoon Mystic on the battlefield
• Scaretiller on the battlefield
• Voltaic Construct on the battlefield
• Crystal Vein on the battlefield
• Viridian Longbow on the battlefield
• Viridian Longbow attached to Scaretiller
• Scaretiller does not have summoning sickness
• Archelos is untapped

Steps

1. Activate Crystal Vein's second ability by tapping and sacrificing it, adding
2. Activate Scaretiller by tapping it
3. Scaretiller triggers, returning Crystal Vein from your graveyard to the battlefield untapped due to Archelos
4. Resolve the Scaretiller ability from step 2, dealing 1 damage to any target
5. Activate Voltaic Construct by paying , untapping Scaretiller
6. Repeat

Results

• Infinite damage
• Infinite landfall triggers