Turn #2: Badger casts Dispel Magic on the cylinder in case there are any protective wards of any kind. (If any spells of 4th level or higher, here are some ability checks: 17, 6, 7)

Turn #3: Badger then casts Knock on the cylinder, just in case that might open the lid and let the captured souls out. (Worth a try, right?)

Turn #4: Finally, Badger casts Bigby's Hand to be positioned directly above the baby-creature. He then walks out of the room back up the stairs to his companions, taking approximately the same position he was in when he cast the spell. He briefly considers swiping Grenk's unicorn horn, but decides it is probably best not to upset the apple cart at this important juncture.

(Amazing how limited the options are. No point casting another concentration spell before Bigby's Hand. Considered Fireball, but wasn't worth the risk of burning the baby by accident. So yeah, might not have been worth casting Time Stop after all. But no regrets, right?)

Ooc: no regerts!

Them neither.

Sighing Mal looks at Badger, "Well are you going to cast the spell from the scroll or not, I am getting impatient."

Badger rolls his eyes and sighs loudly. How long must he suffer these dim-witted surface-dwellers? He wishes he had taken the moment to graffiti their faces again. It would have gone a small way to compensate him for what his patience has to continually endure. It is done. Now, let us enact the rest of the plan - if it is still necessary. Sickle? Keshma? Prepare your barricades!

((Yes, having played bad-guys "as-written" in a few campaigns, I've found that everyone always selects time stop as their bad guys 9th level spell, and its really the worst use of a 9th level spell ever.  Why every wizard wouldn't pick "Wish" or "Prismatic wall" instead is beyond me.  That and usually their prepared spell list doesn't play nice AT ALL with time stop, which is even more terrible. These wizards are idiots apparently!  I think it's done cause they're afraid at how powerful other spells are and it's the least likely to TPK a group.  (crosses out Time Stop on every high level evil mage ever written and writes "wish".  Deal with reality people.  Ok, rant done, moving on.)) 

Everyone stands there a moment as Badger seems to subtly blink in spot. Then you all hear a horrible rending sound from down the stairs, of steel bending and flexing, followed by a crashing smashing sound and the sound like dropping a boulder in a pool of mud.  It's accompanied by a fleshy tearing sound and a screech of pain, and rage that is rather frightening in its intensity. Another more subtle sound of a woosh of wind, but....not a real sound...more a sound in your mind....coming from another place....and relief of fear and death washing away.  This is accompanied by a blinding flash of light from down the stairs, and you're glad you're up here cause it's blinding even bouncing off the walls of the stairwell. 

Round 1 :  (everyone is surprised except Badger, though he may likewise be surprised, who knows...he can still act).  Badger. Your turn.

 [Round 1: Mal: 19, Baby: 17, Badger: 16, Grenk: 14, Silas: 11, Sickle: 8, Keshma: 7, Civilian: 6]

Badger will move back down the stairwell. His intention is to use the giant magic hand (the 'forceful hand' function) to push the baby creature down toward the lava.

Forceful Hand. The hand attempts to push a creature within 5 feet of it in a direction you choose. Make a check with the hand's Strength contested by the Strength (Athletics) check of the target. If the target is Medium or smaller, you have advantage on the check. If you succeed, the hand pushes the target up to 5 feet plus a number of feet equal to five times your spellcasting ability modifier. The hand moves with the target to remain within 5 feet of it.

Hand Strength check: 25.
Maximum push distance: 5 + (5 x 5) = 30 feet.

If he has movement left after doing that, he will move back up the stairwell, hoping to remain out of sight of the baby.

The hand presses down on the sizeable grotesque baby, who grumbles and pushes back...but is unable to resist the push of the hand. With the baby hovering fifteen feet above floor level, the hand presses down on the squirming thing getting it within 15 feet of the hot bubbling lava below.  Then Badger rushes back up the stairs to his friends. 

You all see Badger runs down the stairs, then comes running part way back up. (The stairs are 20 feet down, so he's half way down the stairs at this point.) 

Mal's action.

[Round 2: Mal: 19, Baby: 17, Badger: 16, Grenk: 14, Silas: 11, Sickle: 8, Keshma: 7, Civilian: 6]

Mal will move down the stairs and when she can get an angle on the struts will start firing at the one closest to her.

H. Crossbow: Attack: 14 Damage: 14

H. Crossbow: Attack: 21 Damage: 13

 Precision Attack on 1st bolt if it misses: 5 adds to hit.

Then she will run across the door opening and hide on the other side under the stairs if she can.

Stealth: 14

Mal moves down the stairs and sees a dramatically different situation than what was described to her. The giant metallic tube in the middle of the room, supported by three struts, is gone. Two of the struts hang...twisted, and bent...but the central cylinder is down in the lava below...sinking slowly still...its glass chamber blasted open..****y the metal wreckage slipping into the molten stone. Meanwhile, a giant force hand is pressing the elephant sized grotesque baby down to the lava, having forced it half way down from floor level, down to the lava level in the pit.  It's strange tentacles still thrash about.  

There is no "under" the stairs, the stairway emerges flush with the wall to either side, and really just an open platform on this side of the room with precious little cover. She could duck into one of the bone filled alcoves perhaps and get minimal cover from some angles. 

(Let me know how you'd like to modify your action now that you've moved 25 feet down here...)

Well then I would like to use the same attacks above but then direct my attacks toward the baby thing, but then also apply a Pushing Attack on any attacks that hit.

Pushing Attack 1: 7  Large or smaller creatures DC 17 STR Save or be pushed 15' away from me (hoping I can push down into lava).

Pushing Attack 2: 3  Large or smaller creatures DC 17 STR Save or be pushed 15' away from me (hoping I can push down into lava).

Then just stay at the corner and use my hide there as moving down the stairs took most of my movement and I only have 5' left.

Mal glides down the stairs, and sees the situation.  She fires two arrows down at the huge baby, but as they strike and fail to move it, she realizes it must be too large for her to move with her arrows. The arrows as well fly down and simply bounce off the thick flesh of the creature, seemingly doing no damage.  (It is not a magical attack, correct?) 

Regardless, in response, a blast of cold lashes up at Mal her... Attack: 31 Damage: 14 cold damage.

Then the grotesque thing floats up away from the hand, moving up 15 feet to the floor level, and then another 25 feet higher from the lava until it's near the ceiling...moving over the edge above where Mal is....its long tentacle reaching down.  Near to Mal, an undead creature appears in a vortex of smoke....the creature all smoke and shadow....hovering nearby.  It lunges at Mal.... Attack: 7 Damage: 24 necrotic damage.  

Papazolt whispers into Mal's mind, "That creature looks partially undead....it might be vulnerable to radiant damage.  And...better yet killing it might summon forth Acerack to come see why his creature has been destroyed...with luck we will then be able to face him...and destroy him..." 

Meanwhile, in Badger's mind, Obo'laka is saying, "Watch you, careful....don't fall in the lava.....the bones in those alcoves probably come alive.....watch out for demons emerging from that strange portal on the far side!!"

Badger, Grenk, Silas may all go. 

(FYI, the Baby has 4 tentacles, they can reach 30 feet each.)

[Round 1: Mal: 19, Baby: 17, Badger: 16, Grenk: 14, Silas: 11, Sickle: 8, Keshma: 7, Civilian: 6]

[OOC: Correct non-magical.]

Trying to keep a distance, Silas cast Flame Strike onto the Baby and try to get the wrath in it as well.

Dex save: 16

Damage: 12 Fire / 13 Radiant

Grenk moves down the steps confidently.  He raises his bow glowing with radian energy and fires two of his Yuan-Ti arrows at the baby thing.

Attack: 26 Damage: 11 + 7 poison + Unable to parse dice roll. radiant

Attack: 15 Damage: 8 + 7 poison + Unable to parse dice roll. radiant

Not sure why thos others didn't roll but Unable to parse dice roll., 6

Sigh, 1

Badger again descends the stairs just far enough to spot the baby-thing, and launches a Fireball at it (3rd level, 29 fire damage, DC 17 DEX for half).

He then mentally directs the Bigby's Hand to form a giant fist and fly upwards to punch the baby up against the ceiling.

Bonus Action: Melee attack with Hand: 11 Damage: 19 force damage

With all the potential dangers about from lava and bones and demons and wraiths and tentacles and who-knows-what-else, Badger has no desire to risk staying in harm's way, and escapes back up the stairs.

Silas leaps down the stairs, far enough to be able to look up towards the monstrous thing. Sadly the wraith is just too far from it, but he unleashes a powerful blast of fire that rips through the grotesque creature. 

Flame Strike save: 13

It howls in pain as the flame and holy energy rips through its body...looking very effective, it's blackened flesh bubbling and hissing in the holy light. 

Then Grenk leaps down the stairs past Silas and unleashes two arrows. (As far as I can understand, it appears as if only the rite of the dawn damage is considered magical, the arrow still is not.)  The arrows slam into the creature.  When they strike, there is a searing burn etched across the being, though both arrows go flying away harmlessly. The searing burning energy seems to sizzle the creatures skin very effectively. 

Finally Badger leaps down the stairs. The creatures beady evil eyes glare at the gnome who had already been here.... a fireball leaps from Badgers hands. 

Fireball dex save: 17. The fire roils around the creature who sizzles and screams in pain. Then the giant transparent hand comes flying upwards and slams into the baby's body that seems woefully slow to move...and with a crunch a chunk of bone rips outwards from it chest...leaving a gash that spews blackness....the thing seems staggered.  However, before Badger can escape back up the stairs, a tentacle comes lashing towards him. 

Attack: 26 Damage: 10 necrotic damage. 

Then badger staggers up the stairs away from the thing.

Meanwhile, another tentacle lashes out at Grenk...and attempts to grab him. Attack: 9 Damage: 0. The tentacles tries to wrap around Grenk and pull him out over the lava, but fails to get a good grip and slithers away unsuccessful. 

Sickle strides icy calm down the stairs.  He glances up at the thing with his impassive blue eyes, and raises a hand.  A wall of ice crawls up the along the edge of the pit. It's made up of 4 ten foot stretches at it's base, each with a 3 inch gap between them.  Then, another six panels, all solid, bind the top together, angling backwards and up, merging with the wall behind forming an icy barrier.  

Keshma comes blowing down the stairs like a whirlwind, hammer in hand.  Seeing only an icy wall in front and above her, she glances over at the undead blackness near Mal.  "Ahh..alright, you and I have some business you undead spirit..." 

She flies up to it, and starts swinging. Attack: 13 Damage: 23  Attack: 14 Damage: 17 

Her first blow goes right through the thing, and though it takes a bit of the creatures essence with it, seems less effective....but it also sends her second blow off balance and she misses.  She growls in frustration. 

Nobody is looking back at the Civilian at this point, and so no one notices the evil that it begins to create with its awesome powers.  (Badger glances back and sees him cowering near the top of the stairs, too afraid not to look and to afraid to otherwise move.)

Mal's turn!

[Round 3: Mal: 19, Baby: 17, Badger: 16, Grenk: 14, Silas: 11, Sickle: 8, Keshma: 7, Civilian: 6]

(The ice completely encloses the area it's covering, including blocking any view from the stairs. Though the "front" of the wall does have 3 gaps in it, wide enough to shoot through. NOTE: To use the gaps, you need to walk right up to the gap in the wall and look through, otherwise the field of view is too narrow.)

Mal looks a bit annoyed at all the ice and will take a 5' step back disengaging from the wraith into an alcove and then will fire at the wraith as well.

H. Crossbow: Attack: 18 Damage: 5

H. Crossbow: Attack: 26 Damage: 8

Sneak Attack: 7

Swearing a the ineffectiveness of her attacks.

Mal fires two shots that rip through the wraith and slam into the ice wall on the far side of it, taking a bit of wraith essence with it, but not a lot. 

Baby wraith summoning recharge: 3

The wraith, black smoke and cold energy turns to Keshma, it's visage silently locked in a scream of rage as it attacks her. Attack: 25 Damage: 13. Keshma Con Save: 17 

The baby lets out a terrible wail that echoes through the entire room, assaulting everyone's very soul with it's hideous oppressive wail. 

Con Save DC 19 everyone.  Failure : You gain 1 level of exhaustion. (Level 1 : disadvantage on ability checks. Does not include attacks and saves.) 

Then the massive baby floats down so it's 5 feet above floor level, but can see through a gap in the wall....peering at the gnome who has been hurting it so badly. It opens its mouth and a black wind seems to blow from Badger to the creature as it inhales, pulling at Badgers very soul which it tries to consume.  

Badger, Con Save DC 19.  Take 43 necrotic damage, or half as much on a save.

Finally, while still peering through the notch, a flapping lashing tentacle comes reaching around the outside of the wall of ice and behind it, attempting to latch onto Grenk...

Attack: 10 Damage: 0.

Grenk leaps over the lashing tentacle that tries to grab him and pull him...easily avoiding it. 

At the start of each of your turns this round....the hideous life consuming force of the nearby deadly creature is so close that it sucks at your very life energy....and you take 15 necrotic damage.  (including Badger's Bigby's hand, which has also already taken another 12 necrotic damage)

 Badger, Grenk, Silas, your actions.

[Round 4: Mal: 19, Baby: 17, Badger: 16, Grenk: 14, Silas: 11, Sickle: 8, Keshma: 7, Civilian: 6]

Silas Con Save" 7

"Go back to whatever nightmare plane you came from!" Silas shouts as he attempt to blast the baby with a Guiding Bolt.

Attack: 26 Damage: 12