Felidar Guardian, Conspiracy, Valkyrie's Call, and Altar of Dementia

Prerequisites

• Felidar Guardian on the battlefield
• Conspiracy on the battlefield
• Valkyrie's Call on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Altar of Dementia by sacrificing Felidar Guardian
2. When Felidar Guardian dies, Valkyrie's Call triggers, returning Felidar Guardian from your graveyard to the battlefield as an Angel
3. When Felidar Guardian enters the battlefield, it triggers, blinking Conspiracy
4. Choose any creature type except "Angel" as Conspiracy enters the battlefield
5. Resolve the Altar of Dementia ability
6. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers