Zellix, Sanity Flayer, Haunted One, Pith Driller, Ashnod's Altar, and Faces of the Past

Prerequisites

• Zellix, Sanity Flayer on the battlefield
• Haunted One on the battlefield
• Pith Driller on the battlefield
• Ashnod's Altar on the battlefield
• Faces of the Past on the battlefield
• Zellix does not have summoning sickness
• Pith Driller does not have a +1/+1 counter on it
• available

Steps

1. Activate Zellix by paying and tapping it
2. Haunted One triggers, causing all Horrors you control to get +2/+0 and undying until end of turn
3. Resolve the Zellix ability, causing a player to mill three cards
4. If the player milled a creature card this way, Zellix triggers, creating a 1/1 Horror creature token
5. Activate Ashnod's Altar by sacrificing Pith Driller, adding
6. When Pith Driller dies, its undying ability and Faces of the Past trigger
7. Resolve the Pith Driller trigger, returning it from your graveyard to the battlefield with a +1/+1 counter on it
8. When Pith Driller enters the battlefield, it triggers, putting a -1/-1 counter on it
9. Resolve the Faces of the Past trigger, untapping all Horrors
10. Repeat

Results

• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinitely powerful Horrors you control until end of turn except Pith Driller
• Infinite mill
• Infinite sacrifice triggers
• Infinite self-mill
• Infinite untap of all Horrors
• Near-infinite creature tokens
• Near-infinite LTB
• Near-infinite death triggers
• Near-infinite sacrifice triggers
• Near-infinite colorless mana