Hexavus, and Phyrexian Altar

Prerequisites

• Hexavus on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Activate Phyrexian Altar by sacrificing the undying creature, adding
2. When the creature dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
3. Activate Hexavus' second ability by paying and removing the +1/+1 counter from the undying creature, putting a +1/+1 counter on Hexavus
4. Repeat

Results

• Infinite creature LTB
• Infinite creature ETB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite +1/+1 counters on a creature