((Only two left on BB))

((Make a Perception check, Bolt?))

9

BB smashes the two remaining skitters then, or rather just one since it skitters out of the way of first swing only to get nailed by the second, follow up swing.

To hit attack 1: 8

To hit attack 2: 26
Damage: 18

He will then turn to the last skitter,

"Ya, your turn next. Shuddup."

BB mushes one of the skitterers, while Bolt can see a faint drift of dust atop the ridge where the Robed One vanished, but doesn't have visual on them, presumably they have retreated over the ridge.

((May not be able to gain the top of the ridge this turn, moving or staying put for now?))

Move.

The skitterers swipe at Bolt but miss, she's able to make it nearly to the crest of the rise, and can see the a plume of dust hanging in the air, she's just able to catch a glimpse of movement that drops below the rise. It seems they've been hightailing it out of the area for a bit now.

The skitterers fail to hit, and are seeming a bit uncertain about hanging out to get whommped, but are buying what time they can. The two that had been on Bolt dash after her to harry her departure.

Gramps: 18 (disadvantage on saves, disadvantage on attacks not vs a skitterer)    <-------<<
Black:   (disadvantage on saves, disadvantage on attacks not vs a skitterer)     <-------<<
Larry: 12 (disadvantage on saves, disadvantage on attacks not vs a skitterer)   <-------<<
Bryn: 8    <-------<<
Keller: 8    <-------<<
Robed One: 7 (-115) (invisible, location suspected)
BB: 5 (disadvantage on saves, disadvantage on attacks not vs a skitterer)
Bolt: 2 ( disadvantage on saves, disadvantage on attacks not vs a skitterer) 
Skitterers: 2 (-10/-6 || ?/?/? )

Gramps hops on Black ordering him to move after Bolt and the Skitterers.

In the meantime (as move happens after Gramps turn) he throws a firebolt at the skitterer going after Bolt:

To hit 21 for 11 dmg.

If Black is near an enemy anytime during his turn he'll attack; otherwise he dashes.

in case of attack: to hit 11 for 4dmg.

Gramps snipes a skitterer off of Bolt, and bounds forward on Black.

((Just going to roll d20s for the NPC'd guys... 2, 16, 9, 10, 9, 2))

BB makes good on his threat on the last skitterer, bashing it to mush. As those following Bolt in pursuit crest the ridge, give me Perception checks.

Gramps Perception: 16

BB looks around for something else to smoosh, seeing nothing he takes a breath and raises his arms in victory.

Second wind: 8

He'll then start jogging after the rest of the team.

"Come on Larry."

Gramps sees a fresh puff of dust to point out to Bolt, with her superior 'seeing things that aren't there' vision, and she had already made out the fleeing figure, her spell honing her vision. It seems he hasn't been sticking around, and is currently ~150 feet from Bolt and further from the others.

Bolt lets out a deep rumbling growl, "Coward.  Escape won't be that easy."  Pushing herself forward (Action Surge), Bolt Sprints 60' toward the fleeing figure.  As she runs, she pulls in what sorcerous energies she can from this foreign landscape before unleashing it as an empowered Chaos Bolt.

To put things in a less flavoury way;

Sprint action to move 60' toward the cloaked figure, since 30' may not quite be enough, then Action Surge and Tides of Chaos before casting a 2nd level Chaos Bolt.

Attack: 24 Damage: 11

(I don't even know what's going on with those rolls, everything looks wrong.  Before refreshing the page I saw a 14 to hit and 24 damage, but it wasn't loading the damage roll to determine the damage type, so I don't even know if it did the damage number correctly...)