Unctus, Grand Metatect, The Watcher in the Water, and Keldon Battlewagon

Prerequisites

• Unctus, Grand Metatect on the battlefield
• The Watcher in the Water on the battlefield
• Keldon Battlewagon on the battlefield

Steps

1. During an opponent's turn, activate Keldon Battlewagon by tapping a blue creature you control except Unctus
2. The creature triggers, causing you to loot
3. The Watcher's first ability triggers, creating a 1/1 Tentacle creature token
4. Resolve the Keldon Battlewagon ability
5. Repeat

Results

• Infinite self-discard triggers
• Near-infinite ETB
• Infinite draw triggers
• Infinite looting
• Near-infinite tapped creature tokens
• Near-infinitely powerful Keldon Battlewagon until end of turn