Karn, the Great Creator + Ugin's Nexus + Throne of Geth + Inexorable Tide

Karn, the Great Creator

Ugin's Nexus

Throne of Geth

Inexorable Tide

How it works

1. Activate Throne of Geth by tapping it and sacrificing Ugin's Nexus.
2. Ugin's Nexus is exiled instead of being put into your graveyard, causing you to take an extra turn after this one.
3. Resolve the Throne of Geth ability, putting a loyalty counter on Karn.
4. Activate Karn's second loyalty ability by removing two loyalty counters from it, returning Ugin's Nexus from exile to your hand.
5. Move to your next turn.
6. Cast Ugin's Nexus by paying 5.
7. Inexorable Tide triggers, putting a loyalty counter on Karn.
8. Repeat.

This cunning loop exploits Ugin's Nexus's replacement effect: whenever it hits the graveyard, it exiles itself to grant you an extra turn. By using Throne of Geth to sacrifice the artifact, you trigger this extra turn while conveniently sending Ugin's Nexus into exile, where Karn, the Great Creator can reach out with his second ability to claw it right back to your hand. Once recast, the loop seamlessly restarts, aided by Inexorable Tide and Throne of Geth which effortlessly keep Karn's loyalty counters topped up every step of the way.