Zippy DEX save 5

(I can see both the corpse and Yestabrod, so I get advantage on the saves)
DEX Save against the burst: 11
DEX Save against the spores: 19

Jimjar keeps his distance from the cluster of mushrooms as they seems to release clouds of spores. He then 2 arrows at the first Myconid adult he sees.
Arrow1: 24 damage 8
Arrow2: 8 damage 3
Sneak attack as enemy is in melee: + 9

Grimnir runs once more in the fray and attack one of the Myconid Adult in front of Belwar. With great agility, Grimnir manage to avoid any counter-attack and fall back 20ft away from the enemies after his attacks.
OOC: if it goes down the attack will be dealt on the second one or the Spore servant

MAce 1: 22 damage 5 + 1 Fire
MAce 2: 10 damage 6 + 1 Fire
Bonus action attack: 17 damage 4

Con save: 11

Dex save: 16

Grimnir and Jimjar take out one of the adults, and then Grimnir turns right around and slams a spore servant into the ground. Both fall quiet. Yestabrod mutters and the body of the spore servant explodes, sending guts and fungus flying.

Corpse Burst: DC 12 Dex Save from Derendil, Belwar, and Zippy or take 8 acid damage.

The last remaining spore servant swings at Eldeth with a shortsword:
Attack: 17 Damage: 6

Round 2
20 Grimnir/Jimjar
12 Drow Spore Servants (1 more left)
06 Belwar/Derendil
05 Valrish/Eldeth
05 Myconid Adults (2 more left)
04 Oorr/Zippy
01 Yestabrod (64/75)

Zippy DEX save 21

Dex save: 13

Derendil's Dex save: 13

There can only be one course of action at this juncture.  I cast fireball for 17. 

Edit: OOC: I hate this dice roller. 

Quote from Matthias_von_Schwarzwald >>

There can only be one course of action at this juncture.  I cast fireball for 17. 

Edit: OOC: I hate this dice roller. 

Dex Saves:
Spore Servant: 15
Myconid Adult 1: 7
Myconid Adult 2: 4
Yestabrod: 3 

Flames wash over friend and foe alike as a fireball explodes over the plateau. The spore servant ducks below, the fire singing its back. The Myconids are not as lucky, the bright light of Dawnbringer in their eyes. They don't even see the blast until it's too late. Yestabrod, at the center of the blast, lets the flames wash over him, but what should have been a massive blow to the slug mushroom, evaporates off of him, doing only minor damage.

The spore servant and myconids are failing fast, singed and bruised. Yestabrod seems only a little worse for wear.

Round 2
20 Grimnir/Jimjar
12 Drow Spore Servants (1 more left)
06 Belwar/Derendil
05 Valrish/Eldeth
05 Myconid Adults (2 more left)
04 Oorr/Zippy
01 Yestabrod (56/75)

Quote from AsbestosPenguin >>

Quote from Matthias_von_Schwarzwald >>

There can only be one course of action at this juncture.  I cast fireball for 17. 

Edit: OOC: I hate this dice roller. 

Dex Saves:
Spore Servant: 15
Myconid Adult 1: 8
Myconid Adult 2: 10
Yestabrod: 11 

OOC: Everyone lives.  Of course.  The spore servant is at 5/13, the myconids are at 5/22, and Yestabrod is at 56/75. 

Derendil takes a swipe at the myconid near me (13), killing it instantly (minimum 5 damage), then charges the other one (24), but is a bit dizzy by that point. 

My owl Helps the next attack against the spore servant, then flies out of range. 

<After Derendil's Turn>

Yestabrod mutters more gibberish from his toothy flap and the body of the myconid freshly killed by Derendil explodes, doing 6 acid damage to Derendil, Zippy, and Belwar on a failed DC 12 Dex Saving throw.

Round 2
20 Grimnir/Jimjar
12 Drow Spore Servant (5/13)
06 Belwar/Derendil
05 Valrish/Eldeth
05 Myconid Adult (5/22)
04 Oorr/Zippy
01 Yestabrod (56/75)

Another Dex save (doesn't that thing only have two legendary actions?): 13

And one for Derendil: 19

Valrish slashes at the remaining fungus, while Eldeth engages the servant near her with her dagger:

Valrish:
Attack: 19 Damage: 9
Attack: 23 Damage: 12

Eldeth:
Attack: 7 Damage: 3
Attack: 16 Damage: 6

Zippy DEX saves: 17, 7

Oorr drops the wind magic to conjure an eagle spirit to heal Zippy. "Stay strong, my friend. Together, now!" Zippy stands again and attacks the large fungus... with a bit of reluctance.

Zippy Healing: 6

Zippy Bite: Attack: 19 Damage: 10

Oorr Crossbow: Attack: 9 Damage: 13

Healing Spirit: 9 more turns

Zippy goes down, but a swift spirit of healing from Oorr brings the spider right back up, leaping to attack the larval fungus myconid. The bite and the bolt from Oorr sink deep into the spongy flesh of the creature. 

Yestabrod slumps a few stops towards Grimnir, stopping before it gets too close. Suddenly a cloud of spores fills the air around Yestabrod as they spew forth from oozing pores all over the myconid. 

Zippy, Derendil, Belwar, and Grimnir: DC 12 Con Save from Infestation Spores

Infestation Spores: Yestabrod releases spores that burst out in a cloud that fills a 10-foot-radius sphere centered on it, and the cloud lingers for 1 minute. Any flesh-and-blood creature in the cloud when it appears, or that enters it later, must make a DC 12 Constitution saving throw. On a successful save, the creature can’t be infected by these spores for 24 hours. On a failed save, the creature is infected with a disease called the spores of Zuggtmoy and also gains a random form of indefinite madness (determined by rolling on the Madness of Zuggtmoy table in appendix D) that lasts until the creature is cured of the disease or dies. While infected in this way, the creature can’t be reinfected, and it must repeat the saving throw at the end of every 24 hours, ending the infection on a success. On a failure, the infected creature’s body is slowly taken over by fungal growth, and after three such failed saves, the creature dies and is reanimated as a spore servant if it’s a type of creature that can be.

Zippy CON save: 22

Con save against spores : 4

Derendil first sneezes as he inhales the spores, then his leg starts to twitch, slowly at first, then more quickly and visibly. He picks up his back leg to scratch at this head like a dog, then turns and bites at his left flank. "How undignified..." you hear him mutter, but he doesn't stop.

Grimnir also inhales some of the spores, but instead of itching, looks around at his surroundings, unsure of what exactly is going on. Should they really be fighting this slug thing? It's not all that bad is it? Well, it might be. Who really knows? His friends probably know, but who has time to ask, right?

Yestabrod chuckles loudly. "Yes, softers, breathe deep! The procession is almost starting. I can hear the music already, can't you? Places! Places!" The larval myconid moves closer to Derendil, who is still distracted, scratching, and then Yestabrod turns to face the cave entrance to the Northeast, and the mighty towering mushroom beyond. And then, gradually, you do hear the music. An eerie vocal cadence that rises and falls gently, then sharply, then gentle once more. You think you see figures approaching from deep within the fog in the dim lichen light of the cave about 100 feet away.

(OOC Still in combat)
Round 3
20 Grimnir/Jimjar
12 Drow Spore Servant (All dead)
06 Belwar/Derendil
05 Valrish/Eldeth
05 Myconid Adult (All dead)
04 Oorr/Zippy
01 Yestabrod (44/75)

With only one creature standing, Jimjar and Grimnir are focusing their effort.

Jimjar keeps a good 60ft betwen him and the giant fungus and releases 2 arrows.
Arrow1: 10 damage 5
Arrow2: 18 damage 7
Sneak attack as enemy is in melee: + 7

Grimnir, a bit confused, and coughing forgot about caution and runs into the melee.
OOC: Since he is confused, I will say that he forgot to fall back and stay in melee range (and I will not take the flanking advantage)

Mace 1: 13 damage 8 + 1 Fire
Mace 2: 14 damage 3 + 1 Fire
Bonus action attack: 18 damage 8