Brotherhood Outcast, Phyrexian Altar, and Shade's Form

Prerequisites

• Brotherhood Outcast on the battlefield
• Phyrexian Altar on the battlefield
• Shade's Form on the battlefield

Steps

1. Activate Phyrexian Altar by sacrificing Brotherhood Outcast
2. When Brotherhood Outcast dies, Shade's Form triggers, returning Brotherhood Outcast from your graveyard to the battlefield
3. When Brotherhood Outcast enters the battlefield, it triggers, returning Shade's Form from your graveyard to the battlefield attached to Brotherhood Outcast
4. Repeat

Results

• Infinite creature LTB
• Infinite creature ETB
• Infinite colored mana
• Infinite creature sacrifice triggers
• Infinite death triggers