Cavalier of Night, Phantasmal Image, and Ashnod's Altar

Prerequisites

• Cavalier of Night on the battlefield
• Phantasmal Image on the battlefield
• Ashnod's Altar on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Phantasmal Image, adding
2. When Phantasmal Image dies, its last ability from Cavalier of Night triggers, returning itself from your graveyard to the battlefield as a copy of Cavalier of Night
3. When Phantasmal Image enters the battlefield, its first triggered ability from Cavalier of Night triggers; choose not to sacrifice a creature
4. Repeat

Results

• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers