Crystalline Crawler has at least seven +1/+1 counters on it.
Crystalline Crawler does not have summoning sickness.
Crystalline Crawler and Hellkite Charger cannot be blocked and killed by an opponent.
Steps
Declare Crystalline Crawler and Hellkite Charger as attackers.
Byrke's second ability and Hellkite Charger trigger.
Resolve the Byrke trigger, doubling the number of +1/+1 counters on Crystalline Crawler.
Holding priority, activate Crystalline Crawler's first ability seven times by removing seven +1/+1 counters from it, adding ({5} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Resolve the Hellkite Charger trigger, causing you to pay ({5} magic symbol) ({R} magic symbol) ({R} magic symbol) to untap all attacking creatures you control and to get an additional combat phase after this one.
Repeat each combat phase.
If Crystalline Crawler has at least eight +1/+1 counters on it, this combo nets infinite +1/+1 counter doubling.
Results
Infinite colored mana.
Infinite combat phases.
Infinite +1/+1 counters on creatures you control that have a +1/+1 counter on them.