Koll, the Forgemaster + Demonmail Hauberk + Crookshank Kobolds + Phyrexian Walker

Koll, the Forgemaster

Demonmail Hauberk

Crookshank Kobolds

Phyrexian Walker

How it works

1. Activate Demonmail Hauberk's equip ability by sacrificing Crookshank Kobolds, targeting Phyrexian Walker.
2. When Crookshank Kobolds dies, Koll triggers, returning Crookshank Kobolds from your graveyard to your hand.
3. Resolve the Demonmail Hauberk ability, attaching it to Phyrexian Walker.
4. Cast Crookshank Kobolds by paying 0.
5. Activate Demonmail Hauberk's equip ability by sacrificing Phyrexian Walker, targeting Crookshank Kobolds.
6. When Phyrexian Walker dies, Koll triggers, returning Phyrexian Walker from your graveyard to your hand.
7. Resolve the Demonmail Hauberk ability, attaching it to Crookshank Kobolds.
8. Cast Phyrexian Walker by paying 0.
9. Repeat.

This brilliant loop relies on the zero-mana cost of both Crookshank Kobolds and Phyrexian Walker to constantly recast whichever creature just hit the graveyard. Koll, the Forgemaster turns Demonmail Hauberk's sacrifice-an-artifact-or-creature equip cost into a self-contained recycling engine by instantly bouncing the fallen creature straight back to your hand. Because Demonmail Hauberk allows you to alternate sacrificing your free creatures to itself while shifting the equipment between them, you can repeat this process indefinitely to generate boundless sacrifice, entry, and death triggers.