Necrotic Ooze, Endling, Walking Ballista, and Phyrexian Altar

Prerequisites

• Necrotic Ooze on the battlefield
• Endling in the graveyard
• Walking Ballista in the graveyard
• Phyrexian Altar on the battlefield
• available

Steps

1. Activate Necrotic Ooze using Endling's third ability by paying , giving Necrotic Ooze undying until end of turn
2. If Necrotic Ooze has any +1/+1 counters, activate it using Walking Ballista's second ability by removing a +1/+1 counter from it, dealing 1 damage to any target
3. Repeat step 2 until Necrotic Ooze has no +1/+1 counters
4. Activate Phyrexian Altar by sacrificing Necrotic Ooze, adding
5. Necrotic Ooze dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it
6. Repeat

Results

• Infinite damage
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers