Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight + Sin, Unending Cataclysm + Viscera Seer

Prerequisites

• You control another nontoken creature with base toughness 2 or greater that does not have a -1/-1 counter on it.

Steps

1. 1Activate Viscera Seer by sacrificing the additional creature.
2. 2When the creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. 3Resolve the Viscera Seer ability.
4. 4Activate Viscera Seer by sacrificing Sin.
5. 5When Sin dies, it triggers twice.
6. 6Resolve the first trigger, returning Sin from your graveyard to the battlefield with a -1/-1 counter on it. As Sin enters, remove the -1/-1 counter from the creature sacrificed in step 1, causing Sin to enter with a +1/+1 counter on it instead.
7. 7Resolve the second Sin trigger, putting the counters it had on it when it was sacrificed onto a creature you control and failing to shuffle it into your library as it's no longer in your graveyard.
8. 8Resolve the Viscera Seer ability from step 4.
9. 9Repeat.

Effects

• Infinite +1/+1 counters on creatures you control
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite scry 1