((The big guy is lit up by faerie fire, so Keller's have had advantage. Since the first die of the second chance was a 19, I'll use that as the second die of the first roll. So it's a hit with a 27, doing 21 damage.))

The huge figure lumbers after Keller, allowing Larry to take a swipe at him.

Opportunity Attack: 21 Damage: 12

The creature closes on Keller, and swings down with both meaty fists.

Attack: 25 Damage: 15
Attack: 23 Damage: 11

((If both hit, Keller takes an additional 8 psychic damage, and makes a CON save please!))

Larry manages to connect a punch to the creature's calf, but it is undeterred in its charge on Keller, whiffing with the first, but slamming into the nimble commander with the second.

The lone skitterer takes a snap at Bolt, giggling and snarling.

Attack: 4 Damage: 4

Keller: 21
Grandpa: 19
Black: 19
Larry: 15 (adv on attacks vs)
Brynn: 15
Bolt: 11
Skitterers: 8 (X,X/X/-X/-9/X)
Hulking Figure: 2 (-66)
BB: 2 <---<<
Leader: 2 (-10)

((Suppose Black would have used their reaction to impose disadvantage, but result is the same, the skitterer misses biting Bolt.))

BB grits his teeth and dashes towards the big Boss.

Second wind: 14

(Yeah even with shield that would have hit. Darn.)

Keller CON save, using tides for advantage: 14

(So 12 plus 9, or 12 plus some smaller amount for the damage?)

((CON only needed if both hit, a 14 doesn't hit you, so you're good there. No extra damage, just the 12. And you can hold onto your tides.))

The leader, seeing BB charging it, gives a squawk of surprise and trundles in the direction of the ruins... and the rest of the party that it had sent in to explore.

((The leader is now 120ft from Grandpa, and 85ft from BB.))

Keller: 21  <---<<
Grandpa: 19 <---<<
Black: 19 <---<<
Larry: 15  <---<<
Brynn: 15 <---<<
Bolt: 11 <---<<
Skitterers: 8 (X,X/X/-X/-9/X)
Hulking Figure: 2 (-66)
BB: 2
Leader: 2 (-10)

Bolt slashes into the final skitterer then, if it's dealt with, darts north after the big one.

Attack 1: 18
Damage 1: 13

Attack 2: 25
Damage 2: 5

Bolt's first blow drops the creature silent to the dusty ground, finally silencing the shrieks that had been grating on her misshapen ears.

With the leader bit further again he throws a couple of scorching rays (3rd lvl) to his head

Attack: 12 Damage: 10

Attack: 13 Damage: 12 

Attack: 12 Damage: 2

Attack: 14 Damage: 5  

Keller darts 30 feet south, disengaging with a bonus action. He turns and shoots a ray of frost at the large figure.

Attack: 24 Damage: 9

"Good work on the small ones, this one will take some doing but snipers don't forget about the leader," he says.

Grandpa sends a volley of fire at the departing leader, but the lances of fire fall around the creature, who hisses and jibbers its displeasure.

Keller darts south and sends an icy bolt back at the big one (has faerie fire on it, so ADV roll. 26)

((HAHa!))

The icy blast hits the creature, staggering it a bit as the cold seeps in.

Black moves up to keep near Bolt.

Brynn, having limited options at long range, follows Keller's command phrased as a reminder, and dashes and cunning action dashes after the leader, passing BB.

Larry closes on the hulking figure, unleashing a blur of attacks on them (Tides for advantage on first attack, flurry of blows to follow).

Attack: 23 Damage: 13
Attack: 17 Damage: 10

Attack: 13 Damage: 13
Attack: 20 Damage: 13

Keller: 21
Grandpa: 19
Black: 19
Larry: 15
Brynn: 15
Bolt: 11
Skitterers: 8 (X,X/X/-X/-9/X)
Hulking Figure: 2 (-66)
BB: 2
Leader: 2 (-10)

The first two blows land, but the quick follow up jabs don't find an angle to deal any lasting impact. The creature had already fixed its eyes on Keller, though, and pursues the Commander, swinging down at him with both massive arms.

Attack: 29 Damage: 25
Attack: 20 Damage: 13

IF both hit, 10 psychic damage and Con Save!

Keller: 21
Grandpa: 19
Black: 19
Larry: 15
Brynn: 15
Bolt: 11
Skitterers: 8 (X,X/X/-X/-9/X)
Hulking Figure: 2 (-103)
BB: 2 <-----<<
Leader: 2 (-10)

Keller avoids one of the blows, but gets rocked by the second, the meaty fist slamming down on a shoulder and momentarily forcing him to his knees, where he gets  a good lungful of the purplish dust that has been kicked up by the scuffle.

The creature bellows, spittle spattering down on Keller.

BB dashes towards the leader then pops up next to it already bringing his axe down,

"Hey, what's up?"

Attack: 21 Damage: 9

((Action surge))

(Ouch! I keep thinking I have uncanny dodge but not quite yet...)

((BB, assuming the popping up after moving/dashing the first 60 ft was casting misty step, roll me a d20 wild surge check, then roll a d100 if you roll a 1 on the d20.))

((Wild magics

 ))

BB rushes toward the leader, popping up and whalloping them with his axe. 

((Original hit was a crit.))

The leader staggers from BB's blow, and snarls something in its unintelligible language, before striking at him with it's staff, the weapon moving with surprising speed and force for the creature's apparent bulk.

Staff Attack: 21 Damage: 13 bludgeoning damage, plus 6 psychic damage, and if hit, BB must make a CON Save please!

Tides con save: 17