Corpse Dance + Coretapper + Magistrate's Scepter

Corpse Dance

Coretapper

Magistrate's Scepter

How it works

1. Cast Corpse Dance with buyback by paying 4, returning Coretapper from your graveyard to the battlefield with haste and returning Corpse Dance to your hand.
2. Activate Coretapper's first ability by tapping it, putting a charge counter on Magistrate's Scepter.
3. Activate Coretapper's second ability by sacrificing it, putting two charge counters on Magistrate's Scepter.
4. Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, taking an extra turn after this one.
5. At the beginning of your end step, the delayed ability created by Corpse Dance triggers, failing to exile Coretapper since it is not on the battlefield.
6. Repeat each turn.