Sin, Unending Cataclysm + Thornbite Staff + Ashnod's Altar + Selvala, Heart of the Wilds

Sin, Unending Cataclysm

Thornbite Staff

Ashnod's Altar

Selvala, Heart of the Wilds

How it works

1. Cast Sin either from your hand or command zone by paying 5 plus commander tax if applicable.
2. As Sin enters, remove all counters from all artifacts, enchantments and creatures you control, putting twice that many +1/+1 counters on Sin.
3. Activate Selvala by paying and tapping it, adding at least plus an additional X equal to Sin's power minus 3.
4. Activate Ashnod's Altar by sacrificing Sin, adding CC.
5. Choose to return Sin to the command zone from your graveyard.
6. When Sin dies, it and Selvala trigger.
7. Resolve the Sin trigger, putting its counters on Selvala.
8. Resolve the Selvala trigger, untapping it.
9. Repeat.

This fascinating loop turns Sin, Unending Cataclysm into an infinitely recurring engine by leveraging its massive entry-size to fuel Selvala, Heart of the Wilds. As Sin enters the battlefield, its replacement effect strips counters off your permanents to grow exponentially larger, which in turn causes Selvala to tap for a massive flood of mana. You then feed Sin to Ashnod's Altar, sending it back to the command zone while generating the colorless mana needed to recast it alongside Thornbite Staff, whose static untap ability isn't even needed here because the command zone recast loop resets the whole explosive sequence anew.