Rodolfo will go last. Stealth roll: 9

The rubble blocking the grotto is not difficult to remove.  It is a warning more than a deterrent.  Once inside, the space feels comfortable for everyone but Skameros, who has to hunch over.  This entrance level is simple.  There is a broken basin that would once have held water and several cubbies that have become overgrown with webs and nesting materials of various rodents and creatures.  Leading up is a set of spiral stairs.

As you begin your ascent, distant wails and screams of pain, rage, despair and madness make themselves heard.  Faintly at first but growing steadily louder as you approach the main living level.  You round the final bit of the spiral stairs and enter a chamber that is mostly a half circle, with one side tapering thinner than the other.  The thin side, to the left has a doorway leading into some other rooms.  The chamber is littered with broken stone and dark stains.  There are some nesting materials here too, but fewer.  Scattered among those nests and stone debris are numerous small corpses of innumerable creatures, who met their sudden and surprising end here.

As you survey the scene of centuries of killing and death, the wailing grows suddenly stronger.  "Innocent children.  Curse you you you you.  Eye for an EYE!"  The last word is a screech that almost hurts your brain.  At the same time, you hear another voice, "Make them stop Mommy.  It hurts.  NoooOOOoooo."   Followed by painful yelling.  And behind that voice, the wailing of a terrified child.  All the voices are intertwined and hearing them is disorienting and directionless.

Battle begins.  See OOC thread HERE and HERE for details.  (Make sure you're all Long Rested on your character sheets before we begin)

Skameros goes first.

Skameros swings his greataxe at the ghosts!

Skameros hones in on the wailing, screaming and sobbing, raking his blessed weapon through the form of the Poltergeist, eliciting a horrific screech that causes his ears to ring.  When he swipes a second time, nothing happens.

Having been injured by Skameros, the Poltergeist slams fists into the bugbear, inflicting 15 force damage.

@Rodolfo's turn.

Rodolfo will cast Haste on Beegred. "Go nuts, friend!"

(doesn't look like that shows up in any way in the game log)

Rodolfo waves his hands in intricate arcane patterns, muttering his incantation and Beegred feels everything slow down around him.

After Rodolfo encourages Beegred, a voice make itself heard from the other noises emanating from the Polgergeist, "No mother, make them stop!  Don't let them hurt meeeee!"

With a half-hearted attempt the Poltergeist tries to fling Rodolfo back into the stairwell, but Rodolfo just barely manages to hold his ground.

(The Poltergeist rolled a 3.  Rodolfo saved with a 4......)

(Orubis's turn)

Orubis hears the struggle against Rodolfo and conjures a line of mushrooms which grow with uncanny speed across the floor, and explode upward at the end where he believes the poltergeist is.

It explodes with radiant light, but doesn’t appear to hit anything.

(guiding bolt and a nat 1… oof)

From the Poltergeist, a sobbing wail of fear and despair rises among the cacophony and Orubis launches up into the air, slamming against the ceiling 10 feet above, then falls to the ground prone.

(Poltergeist's CHA check (14) vs. Orubis's STR check (12).  Orubis suffers 7 bludgeoning damage as he slams into the ceiling and slams back onto the ground)

(Beegred's turn)

Beegred whirls around with the magic sword, trying to attack the last locations of the ghost. "Don't hurt my comrades!" But with the sugar rush of being Hastened, all you hear is "rahr rahr rahr", like a tasmanian devil.

The first two strikes connect (26 and 19, with disadvantage and +5 for Observant feat). His Dread Ambusher attack whiffs (11, even with Lucky), but his additional Hastened attack is a bit luckier (15).

The three attacks that connect cause magic sword damage: 6 , 7 , 7  (ugh...)

The cacophony rises to an ear shattering screech as Beegred cuts into the Poltergeist three times faster than the rest of you can blink.

@Grithik's turn

Grithik flips through his tome, his fingers gliding over an unseen passage, he closes his eyes and tethers of divine energy attach to his colleagues.

(Casting Bless on Beegred, Skameros, and himself.)

The mysterious being behind Grithik's powers lends a bit of luck to Skameros, Beegred and Grithik himself.

@Skameros's turn.

Skameros wiffs twice

Skameros tries to determine where the poltergeist is to slash at it, but his guess is wrong.  Then Skameros is distracted by dodging a large chunk of crumbled stone flying straight towards him to strike again.

(Poltergeist tried to fling stone debris at Skameros and missed.  Rodolfo's turn)

Rodolfo takes the Dodge action and stays put.

Rodolfo holds his ground and prepares to evade any attacks sent his way.

The poltergeist attacks the prone Orubis with a spectral blow, inflicting 6 force damage.

(Orubis's turn)

Orubis attempts to stand up and clobber the ghost on him with a magic stone, and flails wildly through empty air

The wails of a sobbing child comes to the forefront of the cacophony of noises emanating from the Poltergeist, and it lashes out at Beegred who takes 6 force damage.

(Beegred's turn)

Beegred swings 3 times with the magic sword (3rd time due to Haste; all with disadvantage and +5 for Observant feat).

The first two strikes barely connect (13, 13), while his sped up blow is better (23 after re-rolling for Lucky).
(Also has Bless, but I assume 14s already hit.)

The three attacks that connect cause magic sword damage: 11 , 10 , 10
(More substandard damage rolls, but the Haste sugar-rush will do that.)