Mephidross Vampire + Walking Ballista
Mephidross Vampire must be on the battlefield. Walking Ballista must be on the battlefield. Walking Ballista has at least two +1/+1 counters on it.
- Activate Walking Ballista's second ability by removing a +1/+1 counter from it, dealing 1 damage to any creature an opponent controls.
- Walking Ballista triggers, putting a +1/+1 counter on itself.
- Repeat as desired.
- You may also repeat this loop whenever a creature enters the battlefield under an opponent's control.
Destroy all creatures that enter the battlefield under an opponent's control. Destroy any number of creatures opponents control. Infinite damage to creatures.