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

Prerequisites

• Xavier Sal, Infested Captain on the battlefield
• Haunted One on the battlefield
• Thornbite Staff on the battlefield
• Phyrexian Altar on the battlefield
• There is at least one counter on a permanent you control except Xavier Sal
• Xavier Sal does not have summoning sickness
• Thornbite Staff attached to Xavier Sal
• You control at least one additional nontoken Human, Fungus and/or Pirate that has no more than one +1/+1 counter on it

Steps

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

Results

• Infinite LTB
• Infinite ETB
• Infinite colored mana
• Infinite sacrifice triggers
• Infinite death triggers
• Infinitely powerful Humans, Fungi and Pirates you control until end of turn