Itsy bitsy spider.

Adrian aims as he runs towards the group sending an arrow infused with his own life force at the massive spider up ahead. It dodges. L turns around in the sticky, slowly dissolving webby goo and breathes lighting at the spider behind her before following up with a swing of her sword. During the time it takes for the spider to counter, she catches her breath in a brief pause.
Irdien runs up to Sirona, facing two spiders, and moves in behind one. She drives one of her daggers in its back.
Jak starts summoning a Horror to aid in their battle and grant redemption, but the spider sees the opening and goes in for a bite. Severely wounded, Jak pulls out a healing potion and downs it in one swoop. In the meantime, The Horror starts attacking the spider between Irdien and Sirona but can't get through its thick skin. The mostly surrounded spider laches out at Irdien, who caused it so much pain before. It injures her, but she hangs on to consciousness. Then the giant spider that Adrian's been aiming for jumps up to the ceiling and bites Irdein with its poisonous fangs. The last prevailing consciousness leaves the drow, and she collapses.
Sirona, too inexperienced to dare move away from her assailants, decides to rescue Irdien with a healing spell that clears up the poison that was still cruising her veins. She gives herself and one of the humanoid cocoons some health back, but the spiders both see their chance and pounce, taking Sirona down while overpowering Labrat and Irdien so they can't use their full potential to fend them off.
Adrain keeps running closer, firing his arrow at the giant beast in the cave ceiling as he goes. Finally, L manages to push the spiders off her enough to get to Sirona's unconscious body and pours a healing potion down her throat. Irdien heads away from the spiders and hurries over to the struggling cocoon, managing to free one of the trapped drows from the previously attacked party. Unfortunately, he is a bit disoriented by eager to join the fight. Irdien hurridly drizzles some magical oil on her blade.
Jak takes an incredible swan dive backwards away from the spider in an attempt to move around. Seeing how badly hurt Sirona still is, he tries to leach some life from one spider and send it to her, but the spell doesn't work. So instead, in frustration, he flings one of his cards at the spider. Impressively, it gets stuck between two of its many eyes. The summoned Horror keeps fighting the spider but gets defeated by it in return as he manages to get the spider's attention away from the others. As it disappears, a gasp of relief is heard.
The gigantic spider takes a swipe at Adrian, who miraculously and skillfully parries the poison dripping fangs from the ceiling. Meanwhile, the newly added drow also pulls the attention of another spider away from the group. Panicking slightly over her inability to move away, Sirona heals herself struggling to figure out what else to do. Then she sees her war pick and remembers that she can hit stuff with the pointy end to cause harm. So she swings it at the spider before her, and it collapses dead on the ground.
There are now two people-sized spiders left and one gigantic. One of the smaller ones attacks L, but she dodges and attacks it back. Adrian takes out his sword and axe and starts hacking at the gigantic spider's face. Irdien joins him in trying to take it down.
Nobody knows for sure how some magic works, but as Jak steps further back, he locks eyes with the colossal abomination and unleashes a vile set of insulting mockery. Somehow his words catch its attention, and as it tries to attack Adrian, instead, it only manages to hurt itself.
L, Sirona and the newly arrived drow continue fighting the smaller sized spiders. At one point, one of them jumps Labrat sinking its fangs into her, but at the last minute, she adjusts her footing so that the armour she is wearing gets shoved into its mouth instead, preventing it from bitting into her.
Adrian hurls a dagger at the legs holding the gigantic spider up at the ceiling. That causes it to losses its grip on the stalactites, and the monster hunter manages to place his sword so that the spider's head gets thoroughly impaled on the way down, killing it. Both he and Irdien quickly turn towards the remaining enemies fighting L and Sirona. Labrat manages to kill her spider off, and after some additional swings and ducking, Jak kills the last spider by shooting an arrow from his bow into the fighting crowd.
As the battle is won, the freed drow turns to irdien, asking in their native tongue where they came from and if they will continue to help. Irdien is wary that the time limit to get back outside of the Underdark is ticking. Jak starts examining further into the cave on his own while Labrat asks if Sirona can heal some of her wounds. Regrettably, Sirona is tapped out, but Adrian steps in using his magical staff to transfer some health from him to L. Ater that, Sirona orders them both to sit down and rest, as Adrian looks like he is about to faint from blood loss. Meanwhile, Jak has found another cocoon and released a second drow. Unluckily, they don't appear to speak common, so to ease their confusion Jak plays a song he's learned that's written in the drow language. He doesn't know what the words mean precisely but pronounces them flawlessly. It does intrigue the rescued drows. Moving further in, Irdien and Jak help free a female drow that is the group's commander. She is angry, wondering if her brother is here. After asking her name, it's clear that her brother was the one that ran to get help. Irdien points that out trying to give the deserter some leeway. The woman is not convinced and seems angry that Irdien has technically proven herself a more skilful fighter than her. A tad begrudgingly, the commander hands over her daggers as a thank you. Irdien accepts the gift with a bow. Then the commander says that they better hurry back from where they came from if they want to leave the Underdark tonight.