Pentavus, Necrosynthesis, and Ashnod's Altar

Prerequisites

• Pentavus on the battlefield
• Necrosynthesis on the battlefield
• Ashnod's Altar on the battlefield
• available

Steps

1. Activate Pentavus' first ability by paying and removing a +1/+1 counter from it, creating a 1/1 Pentavite creature token
2. Activate Ashnod's Altar by sacrificing the Pentavite, adding
3. The Pentavite dies, triggering Pentavus, putting a +1/+1 counter on itself
4. Repeat

Results

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