Bright-Palm, Soul Awakener + Crystalline Crawler + Hellkite Charger

Bright-Palm, Soul Awakener

Crystalline Crawler

Hellkite Charger

How it works

1. Declare Bright-Palm and Hellkite Charger as attackers, triggering their abilities.
2. Resolve the Bright-Palm trigger, doubling the number of +1/+1 counters on Crystalline Crawler.
3. Activate Crystalline Crawler's first ability seven times by removing seven +1/+1 counters from it, adding 5.
4. Resolve the Hellkite Charger trigger, causing you to pay 5 to untap all attacking creatures you control and to get an additional combat phase after this one.
5. Repeat.