Walking Ballista + Unspeakable Symbol + City on Fire

Walking Ballista

Unspeakable Symbol

City on Fire

How it works

1. Give Walking Ballista lifelink, if needed.
2. 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.
3. Activate Walking Ballista's second ability by removing a +1/+1 counter from it, dealing 3 damage to an opponent or a permanent an opponent controls, and causing you to gain 3 life.
4. Repeat from step 2.