The Watcher in the Water, Wylie Duke, Atiin Hero, Heart of Kiran, Shilgengar, Sire of Famine, and Maskwood Nexus

Prerequisites

• The Watcher in the Water on the battlefield
• Wylie Duke, Atiin Hero on the battlefield
• Heart of Kiran on the battlefield
• Shilgengar, Sire of Famine on the battlefield
• Maskwood Nexus 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 Shilgengar 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 Shilgengar ability, creating a Blood token
8. Repeat

Results

• Infinite card draw
• Near-infinite lifegain
• Near-infinite lifegain triggers
• Near-infinite ETB
• Infinite draw triggers
• Near-infinite LTB
• Near-infinite death triggers
• Near-infinite sacrifice triggers
• Near-infinite Blood tokens