Dawnsire, Sunstar Dreadnought | Vigor | Crystalline Crawler

(and one other card)

You control a creature that can attack and that cannot be blocked and killed by an opponent.

Declare any creature as an attacker, triggering
Najeela if the creature was a Warrior and
Dawnsire.
Resolve the
Najeela trigger, if applicable, creating a 1/1 Warrior creature token that is tapped and attacking.
Resolve the
Dawnsire trigger, attempting to deal 100 damage to
Crystalline Crawler, which will result in 100 +1/+1 counters being placed on it instead due to
Vigor.
Holding priority, activate
Crystalline Crawler's first ability five times by removing five +1/+1 counters from it, adding ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) .
Activate
Najeela by paying ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) , untapping all attacking creatures, giving them trample, lifelink and haste, and causing you to get an additional combat phase after this one.
Repeat each combat phase.

As long as
Crystalline Crawler has enough +1/+1 counters on it, you do not need to target it in step 1, allowing you to put +1/+1 counters on other creatures you control if desired.