Chainer, Nightmare Adept + Coretapper + Magistrate's Scepter

Chainer, Nightmare Adept

Coretapper

Magistrate's Scepter

How it works

1. Activate Coretapper's first ability by tapping it, putting a charge counter on Magistrate's Scepter.
2. Activate Coretapper's second ability by sacrificing it, putting two charge counters on Magistrate's Scepter.
3. Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, taking an extra turn after this one.
4. During your next extra turn's main phase, activate Chainer by discarding a card, allowing you cast Coretapper from your graveyard this turn.
5. Cast Coretapper by paying 2.
6. When Coretapper enters the battlefield, Chainer triggers, giving Coretapper haste until your next turn.
7. Repeat each turn.

This ingenious loop leverages Coretapper to effortlessly fuel Magistrate's Scepter's extra-turn ability on the spot, since sacrificing Coretapper immediately supplies the final two charge counters needed after a simple tap ability adds the first. Because Chainer, Nightmare Adept grants you the ability to cast a creature spell from your graveyard once per turn—and instantly gives Coretapper haste upon re-entry thanks to its built-in trigger—you can seamlessly loop this artifact back out of the graveyard every single turn. By repeatedly sacrificing, casting, and recurring Coretapper, you perpetually fund Magistrate's Scepter to take infinite turns and lock your opponents out of the game entirely.