Necrotic Laboratory

Necromancer's hexagram in the centre of the lab

The Necrotic Laboratory is a Location within the Shadow-Cursed Lands in Act Two of Baldur's Gate 3. It is part of the Mind Flayer Colony located in the south-east (entrance X: 715 Y: -50) and connected directly to its other part, Morgue.

General details

Upon entering the area, a battle with a large number of undead commences, including: one Death Shepherd (lv.6), four Winged Horrors (lv.3), four Greater Zombies (lv.7), and six Zombies (lv.3). During the battle, the Death Shepherd casts  No Rest for the Wicked, rising two Reconstituted Duellists, a Reconstituted Marksman and a Reconstituted Arcanist (one of those per round).

In the centre of the Necrotic Laboratory resides a huge hexagram with a Profane Womb at each apex. Should the party help Balthazar reach the Nightsong in the Gauntlet of Shar and allow the necromancer take her away, all party members fall unconscious in the Shadowfell and wake up in these containers. They bestow the  Profane Womb-Bound Condition, which silences its victims and keeps them in place.

Brain Puzzle

Initial set of the mind puzzle

In the far southeast corner of the laboratory stands a neural button. Activating it brings forth an imaginary projection with a Brain Mapping Puzzle, consisting of four mental faculties (Emotion, Speech, Memory, and Reason). To solve this puzzle each faculty must be connected to its matching copy on the far side of the puzzle by selecting intervening nodes, avoiding overlaps. Successfully solving the puzzle grants the 'Brain Blast!' Inspirational Event to characters with Sage background.

Desecrated Relief

Behind the puzzle projection is a locked Flesh-Wrought door. It cannot be opened neither by lockpicking or using  Knock; only by solving the brain puzzle. Once opened, it reveals a Desecrated Relief, which can be activated. Looking at the relief prompts several patchy, descriptive phrases, projected into the character's mind by the Absolute. Afterwards, the Dream Guardian comments on it, explaining that the relief is a depiction of the Grand Design - a universal concept, and the implementation of which is the supreme desire of all illithids and all Elder Brains.

Nearby, in the heap of skulls at X: 750 Y: -138, the party can find the Blade of Oppressed Souls and a brain jar with the Waking Mind. Beside the jar lies a skeleton with the Circlet of Mental Anguish and Braindrain Gloves on it.

Balthazar's in-colony study

To the west of the hexagram is located a small study with a desk and the Mind-Archive Interface nearby at X: 699 Y: -117. This device allows party members to talk with the brains in the green jars found scattered across the colony, through the Slack-Skinned Head installed on it. Balthazar's Notes left on the desk reveal that this interface is an invention of Enver Gortash.

There are eight brain jars available to find and use in the Mind-Archive Interface. Six of them (True Mind, Willing Mind, Waking Mind, Butchered Mind, Closed Mind and Fresh Mind) can be found in the colony itself, while two others (Dark Mind and Slave Mind) can be picked up on the Nautiloid in the Prologue.

Of all those, the only item of practical use is the Waking Mind. If spoken to, it appears to be the brain of a Githzerai Monk, preserved by mind flayers long ago as a trophy and a delicacy. It can grant a permanent buff to the party member who spoke to it:  Githzerai Mind Barrier, in exchange for the promise to purge it afterwards.

All other brains only give dialogue, though some cast a bit of light upon Balthazar's and Gortash's cooperative experiments in creating magically enhanced tadpoles and honing their impact on infested victims.

Also on the desk lay Mol's Eyepatch and a Resonance Stone. Picking up the Eyepatch updates the  Find Mol quest. The Resonance Stone radiates magical energy which provides all characters within 9 meters with  Steeped in Bliss. Prayer for Forgiveness laying nearby gives some hints concerning the history of the Dark Urge origin.

The last notable items on the desk are two Rune Slates, each requires passing a DC 14 Arcana check to be read. Unlike slates found on the Nautiloid, here the inscribed text does not appear as a Narrator line, but written on a grey-coloured paper list (similar to a book layout). Both slates tell of the fall of the Illithid Empire and the fate of the Elder Brain managing the colony.