Reaper King + Wingrattle Scarecrow + Metallic Mimic

Reaper King

Wingrattle Scarecrow

Metallic Mimic

How it works

1. Cast Wingrattle Scarecrow by paying 3.
2. Wingrattle Scarecrow enters the battlefield with a +1/+1 counter on it due to Metallic Mimic.
3. Reaper King triggers, destroying Wingrattle Scarecrow.
4. Wingrattle Scarecrow dies, triggering its persist ability, returning it to the battlefield with no -1/-1 counters due to Metallic Mimic.
5. Repeat from step 3.