The Watcher in the Water, Wylie Duke, Atiin Hero, Heart of Kiran, Bartolomé del Presidio, and Xenograft

Prerequisites

• The Watcher in the Water on the battlefield
• Wylie Duke, Atiin Hero on the battlefield
• Heart of Kiran on the battlefield
• Bartolomé del Presidio on the battlefield
• Xenograft on the battlefield
• Wylie Duke does not have summoning sickness
• It is an opponent's turn

Steps

1. During an opponent's turn, activate Heart of Kiran by tapping Wylie Duke
2. Wylie Duke triggers, causing you to draw a card and gain 1 life
3. The Watcher's first ability triggers, creating a 1/1 Tentacle creature token
4. Resolve the Heart of Kiran ability, causing it to become a creature until end of turn
5. Activate Bartolomé del Presidio by sacrificing the Tentacle
6. When the Tentacle dies, The Watcher's second ability triggers, untapping Wylie Duke and putting a stun counter on up to one permanent
7. Resolve the Bartolomé del Presidio ability, putting a +1/+1 counter on it
8. Repeat

Results

• Infinite card draw
• Near-infinite lifegain
• Near-infinite lifegain triggers
• Near-infinite ETB
• Near-infinite LTB
• Near-infinite death triggers
• Near-infinite sacrifice triggers
• Near-infinite +1/+1 counters on Bartolomé del Presidio
• Infinite draw triggers