Queen Araneae

"Rumor holds that Archbishop Lazarus loosed a silent terror in the caves near Leoric's manor before he died. He labored for weeks over a group of unusually large spiders, and many of his servants quietly disappeared during this time....The largest creature led the others into the caves. None who have ventured there have returned."

- Deckard Cain

Queen Araneae, The Shadow Weaver, is a mid-act boss monster in of Diablo III.

Biography
"Please, help me. It’s horrible. She sucks the innards from the victims. No! It's too late, I hear her! The spider queen is coming!"

- Karyna

During the Darkening of Tristram, Araneae was enslaved (or created) by Lazarus. Leoric, wary of the people of Tristram threatening his manor, ordered the nearby caves be sealed. To this end, Lazarus spent weeks working on a group of spiders. Araneae was the largest of the creatures, and she led the other spiders into the caves. After this, none who entered the caves ever returned.

Two decades later, Araneae bound Karyna. However, she was rescued by The Nephalem, who slew Araneae in the ensuing battle.

In-game
Araneae is found in the Caverns of Araneae during the "Trailing the Coven" quest in Act I.

Upon entering the Chamber of Queen Araneae, players behold a woman trapped in a spider web, blocking the exit to the chamber. Approaching her will summon Araneae. Back track immediately into the centre of the chamber, otherwise you may be trapped up the steps against the web, with no ability to roll past Araneae when the fight commences.

The fight takes place in an oval cave, with a small square pit in the middle. Note that this pit is impassable for the player, but counts as clear terrain for the spider queen, so circling kiting will not work for this fight.

During the fight, she will leave this area to hide (when she loses 25% and 50% of health), summoning her minions (five Brood Daughters) to fight you, returning when they are killed. The queen attacks by either biting the player or pouring poison (latter is a channeled attack), and can summon Plagued pools at will. Unlike common Toxic Lurkers, she may create more than one pool of venom at a time.

On Torment difficulty, Queen Araneae has no enrage timer.

After defeating the spider queen, Karyna tells you to use some of the venom from a nearby pool to release her. After doing so, she asks if they can "leave this terrible place".

Queen Araneae is a bounty in the game's Adventure Mode. However, killing her is much easier than getting to her, especially finding her cave in the Caverns of Araneae.

Trivia

 * Araneae may be named in reference to Arachne; a mortal woman turned into a spider in Greek mythology.