Walking Ballista, Unspeakable Symbol, Quest for Pure Flame, and Twinflame Tyrant

Prerequisites

• Walking Ballista on the battlefield
• Unspeakable Symbol on the battlefield
• Quest for Pure Flame on the battlefield
• Twinflame Tyrant on the battlefield
• Quest for Pure Flame has at least four quest counters on it
• You have a way to give Walking Ballista lifelink
• Walking Ballista has at least two +1/+1 counters on it, or your life total is at least 4

Steps

1. Activate Quest for Pure Flame by removing four quest counters from it and sacrificing it, doubling all damage you deal this turn
2. Give Walking Ballista lifelink, if needed
3. If Walking Ballista has less than two +1/+1 counters on it, activate Unspeakable Symbol by paying 3 life, putting a +1/+1 counter on Walking Ballista
4. Activate Walking Ballista's second ability by removing a +1/+1 counter from it, dealing 4 damage to an opponent or a permanent an opponent controls, and causing you to gain 4 life
5. Repeat from step 3

Results

• Infinite damage
• Infinite lifegain triggers
• Infinite lifegain
• Infinite +1/+1 counters