Xathrid Necromancer + Viscera Seer + Conspiracy

Xathrid Necromancer

Viscera Seer

Conspiracy

How it works

1. Activate Viscera Seer by sacrificing any other creature.
2. When the creature dies as a Human due to Conspiracy, Xathrid Necromancer triggers, creating a 2/2 Zombie creature token.
3. Resolve the Viscera Seer ability.
4. Repeat.

The genius of this loop lies in Conspiracy, which rewrites the identity of your entire deck to make every single creature you control count as a Human. With that blanket type-shifting in place, sacrificing a creature to Viscera Seer causes Xathrid Necromancer to trigger upon its death and yield a replacement 2/2 Zombie token. Because that new token is *also* retroactively treated as a Human thanks to Conspiracy, you can feed it right back into Viscera Seer to repeat the cycle indefinitely.