Ulamog's Dreadsire, Thornbite Staff, and Altar of Dementia

Prerequisites

• Ulamog's Dreadsire on the battlefield
• Thornbite Staff on the battlefield
• Altar of Dementia on the battlefield
• Thornbite Staff attached to Ulamog's Dreadsire
• Ulamog's Dreadsire does not have summoning sickness

Steps

1. Activate Ulamog's Dreadsire by tapping it, creating a 10/10 Eldrazi creature tokens
2. Activate Altar of Dementia by sacrificing the Eldrazi token
3. When the Eldrazi token dies, Ulamog's Dreadsire triggers, untapping Ulamog's Dreadsire
4. Resolve the Altar of Dementia ability, causing target player to mill cards equal to the Eldrazi's power
5. Repeat

Results

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