The Watcher in the Water + Wylie Duke, Atiin Hero + Heart of Kiran + Shilgengar, Sire of Famine + Amoeboid Changeling

The Watcher in the Water

Wylie Duke, Atiin Hero

Heart of Kiran

Shilgengar, Sire of Famine

Amoeboid Changeling

How it works

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

This intricate loop turns Wylie Duke, Atiin Hero into a one-man engine by using Amoeboid Changeling to temporarily grant him the Kraken creature type, allowing him to benefit from The Watcher in the Water's untap trigger. Tapping Wylie Duke to crew Heart of Kiran triggers his ability to draw a card and gain life, which simultaneously spawns a Tentacle token via The Watcher in the Water's opponent's-turn trigger. You then feed that freshly made Tentacle to Shilgengar, Sire of Famine to produce a Blood token; that death triggers The Watcher in the Water to untap Wylie Duke, letting you tap him right back down to crew the Vehicle and repeat the entire sequence.