Enduring Renewal + Phyrexian Altar + Cubwarden + Centaur Omenreader

Enduring Renewal

Phyrexian Altar

Cubwarden

Centaur Omenreader

How it works

1. Cast Cubwarden for its mutate cost by paying , targeting a non-Human creature you control.
2. The Cubwarden mutated creature triggers, creating two 1/1 Cat creature tokens.
3. Activate Phyrexian Altar by sacrificing the Cubwarden mutated creature, adding .
4. When the Cubwarden mutated creature dies, Enduring Renewal triggers, returning Cubwarden and any cards merged with it from your graveyard to your hand.
5. Activate Phyrexian Altar by sacrificing a Cat token, adding .
6. Repeat.

This loop turns the battlefield into a recursive engine by leveraging Enduring Renewal's replacement effect, which neatly bypasses normal card draw while immediately returning any creature that dies from the battlefield straight back to your hand. You feed the mutated stack into Phyrexian Altar to generate the mana needed to recast it, while Cubwarden provides a steady stream of Cat tokens whenever it mutates to help fuel your sacrifice outlets. Meanwhile, Centaur Omenreader waits in the wings, ready to discount your creature spells once tapped so you can keep the loop flowing endlessly without running out of mana.