Gnawing Vermin, Underworld Breach, Phyrexian Altar, and Panharmonicon

Prerequisites

• Gnawing Vermin on the battlefield
• Underworld Breach on the battlefield
• Phyrexian Altar on the battlefield
• Panharmonicon on the battlefield
• You have at least three cards in your graveyard

Steps

1. Activate Phyrexian Altar by sacrificing Gnawing Vermin, adding
2. Gnawing Vermin dies, triggering its second ability, causing target creature you don't control to get -1/-1 until end of turn
3. Cast Gnawing Vermin from your graveyard for its escape cost by paying and exiling three other cards from your graveyard
4. Gnawing Vermin enters the battlefield, triggering its first ability twice, causing you to mill four cards
5. Repeat

Results

• Infinite self-mill
• Near-infinite death triggers
• Near-infinite ETB
• Near-infinite LTB
• Near-infinite mill
• Near-infinite sacrifice triggers
• Near-infinite storm count