Xavier Sal, Infested Captain + Haunted One + Thornbite Staff + Phyrexian Altar

Xavier Sal, Infested Captain

Haunted One

Thornbite Staff

Phyrexian Altar

How it works

1. Activate Xavier Sal's first ability by tapping it and removing a +1/+1 counter from the additional nontoken Human, Fungus and/or Pirate if it has one, or any counter from another permanent you control otherwise.
2. Xavier Sal triggers, causing it and all other creatures you control that share a creature type with it to get +2/+0 and gain undying until end of turn.
3. Resolve the Xavier Sal ability, causing you to populate.
4. Activate Phyrexian Altar by sacrificing the additional Human, Fungus and/or Pirate, adding one mana of any color.
5. When the creature dies, its undying ability and Xavier Sal trigger.
6. Resolve the creature's undying trigger, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
7. Resolve the Xavier Sal trigger, untapping it.
8. Repeat.

This intricate loop turns Xavier Sal, Infested Captain into an unstoppable engine of life and death, supercharged by Haunted One granting your commanders the undying keyword whenever they tap. By equipping Thornbite Staff to Xavier, you gain both a ranged damage outlet and the vital untap trigger whenever any creature bites the dust, allowing you to feed creatures directly into Phyrexian Altar for colored mana. As those creatures die and return via undying, Xavier's own triggered ability resets him for another activation, generating an infinite cascade of sacrifices, enters-the-battlefield effects, and colored mana.