The Watcher in the Water + Wylie Duke, Atiin Hero + Heart of Kiran + Phyrexian Altar + Maskwood Nexus

The Watcher in the Water

Wylie Duke, Atiin Hero

Heart of Kiran

Phyrexian Altar

Maskwood Nexus

How it works

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 Phyrexian Altar 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. Repeat.

This intricate engine centers on Wylie Duke, Atiin Hero, whose tap ability rewards you with a life and a card draw, instantly feeding The Watcher in the Water's desire for opponent-turn card draw to churn out a Tentacle token. Maskwood Nexus binds the entire loop together by granting every creature type to your board, making that freshly minted Tentacle also a Kraken that can cleanly satisfy The Watcher's dying-trigger requirement. From there, you simply sacrifice the token to Phyrexian Altar for mana while utilizing Wylie Duke to bypass traditional crew costs via Heart of Kiran, causing the dying Tentacle's trigger to untap Wylie Duke and prep the loop to run again.