Clockspinning + Thousand-Year Storm + Crystalline Crawler

Clockspinning

Thousand-Year Storm

Crystalline Crawler

How it works

1. Cast Clockspinning with buyback by paying 3, targeting Crystalline Crawler.
2. Thousand-Year Storm triggers, creating a copy of Clockspinning targeting Crystalline Crawler for each other instant and sorcery you've cast each turn.
3. Resolve all copies of Clockspinning, putting that many +1/+1 counters on Crystalline Crawler.
4. Resolve the original Clockspinning, putting a +1/+1 counter on Crystalline Crawler and returning Clockspinning to your hand.
5. Activate Crystalline Crawler's first ability four times by removing four +1/+1 counters from it, adding 3.
6. Repeat.