Gatta and Luzzu + Hardened Scales + Walking Ballista
Gatta and Luzzu
Hardened Scales
Walking Ballista
Infinite damageInfinite +1/+1 counters on a creature
How it works
Cast Gatta and Luzzu by paying 2.
When Gatta and Luzzu enters the battlefield, it triggers, targeting Walking Ballista.
Activate Walking Ballista by removing a +1/+1 counter from it, targeting itself, but instead putting two +1/+1 counters on it due to Gatta and Luzzu and Hardened Scales.
Activate Walking Ballista by removing a +1/+1 counter from it, dealing 1 damage to any target.