Hexavus + Phyrexian Altar

Hexavus

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing the undying creature, adding 1.
2. When the creature dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. Activate Hexavus' second ability by paying 1 and removing the +1/+1 counter from the undying creature, putting a +1/+1 counter on Hexavus.
4. Repeat.

By cycling an undying creature back and forth between the battlefield and the graveyard, this loop turns Phyrexian Altar into a self-sustaining engine where the creature's dying sacrifice triggers its own return. Hexavus is the crucial linchpin that makes this endless recursion possible, using its ability to strip away the +1/+1 counter that would otherwise permanently lock the creature out of triggering undying again. The result is a perpetual motion machine that generates infinite deaths, sacrifices, and ETBs while pumping up Hexavus to astronomical proportions.