MTG >Combos >Ugin's Nexus +Throne of Geth +Karn's Bastion +Karn, the Great Creator +

Sacrifice Ugin's Nexus with Throne of Geth to proliferate, put a Loyalty counter on Karn Ugin's Nexus will be exiled, and you will play an extra turn Use Karn's Bastion to proliferate and put another loyalty counter on Karn Use Karn's -2 ability to fetch Ugin's Nexus from exile. Repeat the process.