Crystalline Crawler + Dancing from Dark to Dawn + Cavern Harpy

Crystalline Crawler

Dancing from Dark to Dawn

Cavern Harpy

How it works

1. Cast Cavern Harpy by paying its mana cost.
2. Dancing from Dark to Dawn's first ability triggers, putting two +1/+1 counters on Crystalline Crawler.
3. Resolve the Cavern Harpy spell. When it enters, it triggers, returning itself from the battlefield to your hand.
4. Activate Crystalline Crawler twice by removing two +1/+1 counters from it, adding
5. Repeat.