Thraben Doomsayer, Thornbite Staff, and Altar of Dementia

Prerequisites

• Thraben Doomsayer on the battlefield
• Thornbite Staff on the battlefield
• Altar of Dementia on the battlefield
• Thraben Doomsayer does not have summoning sickness
• Thornbite Staff attached to Thraben Doomsayer

Steps

1. Activate Thraben Doomsayer by tapping it, creating a 1/1 Human creature token
2. Activate Altar of Dementia by sacrificing the Human
3. When the Human dies, Thraben Doomsayer triggers, untapping Thraben Doomsayer
4. Resolve the Altar of Dementia ability, causing target player to mill cards equal to the Human's power
5. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite mill
• Infinite self-mill
• Infinite damage