"Jus' a pit in the floor." The kobold jabs his tail at a crack running along the ground in front of him. Belleres' inspection reveals no reason to disbelieve it.

Drueze pushes the Kobold onto the crack 

Necria loosens her grip on the rope, allowing the kobold to fall if he triggers the trap, letting the rope slide through her gloved hand, and then attempting to lower him safely to the bottom of the pit. 

With a crash and puff of dust, the section of floor gives way, swinging to the far side of a good-sized pit. Squealing, tail lashing frantically, the kobold clutches the rope as he slides down ten feet, scrabbling against the rock. Then he lets out a shrill scream. As you look down, you see a swarm of glossy black centipedes boiling over the kobold, clicking their barbed mandibles.

What do you do?

Necria pulls the rope back up, hoping to rescue the kobold before he’s consumed. 

The kobold gags on the rope for a second, then flops back onto the ledge, shaking centipedes off like a dog does water. But the skittering sound is growing louder...it seems a wave of centipedes is swarming out of the pit.

Can everyone roll initiative?

Inititave 17

Initiative: 20

Initiative 2

Belleres will grab a torch from their pack and use the druidcraft cantrip to light it.  Eventually Belleres will sweep the torch in front of themselves at the insects, but that might be too much for one turn.

Initiative: -1

Jharn grabs out a jar of oil and throws it at the edge of the pit, hoping that it will break and splash over the centipedes. "Can somebody light this?!"

The oil pools over the space the centipedes are currently occupying. (Their turn will be between Drueze's and Necria's).

Belleres will touch the torch in the oil ASAP.

On his turn Drueze will swing his staff at a centipede Attack: 16 Damage: 6 and take a kick if he sees one not on fire. Attack: 23 Damage: 4

Drueze sends centipedes flying, bouncing off the walls with a sickening crunch. The oil-covered remainder, however, swarms over him like a rippling blanket, biting with their clicking pincers.

Drueze is hit for 9 damage.

Necria drops the rope and gestures with her free hand while she utters an incantation, casting sacred flame. Flame-like radiance descends on the swarm. DC 11, 1 radiant damage. 

She moves a full 30 feet back down the tunnel, away from the swarm. 

“Sorry mates,” she says to her companions, “I thought the pit might be a good place to store the little bugger.”

The swarm fails its saving throw, and a few centipedes explode with radiant light. It is still covered in oil, but it's also occupying the same space as Drueze. We're back at the top of the order with Belleres.

Jharn attacks the swarm, being careful not to hit Drueze. She then backs out of the tunnel, allowing someone else to attack or Drueze to try and get away from the centipedes. 

Attack: 14 Damage: 8

Belleres will yell out to Dreuze.  "Roll on the ground, try to squash them." Belleres will hold their action until the swarm are free of Dreuze. When they are, Belleres will attack with their staff, believing that it will now be dangerous to set them on fire.

 Attack: 8

Damage: 10

Can I do a nature or animal handling check to see what I know about centipedes?  Perhaps that will help us fight them.

Nature check: 22

Animal handling check: 11