Phyrexian Altar + Bloodsoaked Champion + Skeleton Crew

Phyrexian Altar

Bloodsoaked Champion

Skeleton Crew

How it works

1. Activate Phyrexian Altar by sacrificing Bloodsoaked Champion, adding .
2. Activate Bloodsoaked Champion by paying 1, returning it from your graveyard to the battlefield.
3. Skeleton Crew triggers, creating a creature token.
4. Activate Phyrexian Altar by sacrificing the creature tokens, adding 1.
5. Repeat.

This elegant loop uses Phyrexian Altar as both the sacrificial outlet and the mana engine to fund Bloodsoaked Champion, which continually recurs from the graveyard. While the Champion's raid cost usually restricts when it can return, the engine bypasses this limitation once it gets rolling because Skeleton Crew turns those recurring trips into a steady stream of 2/2 tokens. Each sacrificed token then provides the extra mana needed to sustain the loop indefinitely, generating an endless cascade of deaths, leaves-the-graveyard triggers, and sacrifices.