Ivy Lane Denizen + Viscera Seer

Steps

1. Activate Viscera Seer by sacrificing the creature with persist.
2. The persist ability triggers, returning that creature to the battlefield with a -1/-1 counter.
3. Ivy Lane Denizen triggers, putting a +1/+1 counter on the persist creature.
4. Resolve the ability from step 1, scrying 1.
5. Repeat.