Xathrid Necromancer, Maskwood Nexus, and Phyrexian Altar

Prerequisites

• Xathrid Necromancer on the battlefield
• Maskwood Nexus on the battlefield
• Phyrexian Altar on the battlefield
• You control at least one additional creature

Steps

1. Activate Phyrexian Altar by sacrificing any other creature, adding one mana of any color
2. The creature dies, triggering Xathrid Necromancer, creating a 2/2 Zombie creature token
3. Repeat

Results

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