Baldur's Gate 3 (BG3)

How to Solve the Necrotic Laboratory and Location

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This is a guide on how to get to the Necrotic Laboratory in the Mind Flayer Colony and solve its puzzle in Baldur's Gate 3 (BG3). Learn about the Necrotic Laboratory puzzle solution, as well as explore the nearby interface that uses humanoid brains (Minds).

Side Quest Details

Journal Entry
Defeat Ketheric Thorm
Recommended Level Lv. 8
Rewards • Blade of the Oppressed
• Githzerai Mind Barrier
Location
Mind Flayer Colony
X: 716 Y: -91
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Necrotic Laboratory Brain Puzzle

Necrotic Laboratory Puzzle Solution

Puzzle Solution Top View
Puzzle Solution Side View

The brain puzzle can be redone at any time by interacting with the console.

Next to the central room of the laboratory is a Brain Puzzle that is solved using nodes to connect organs of matching color. The rules for completing the puzzle is a follows:

  • Connect identical organs from one end to the other through nodes.
  • No two organ pathways (or colors) can intersect in a node.
  • All four organs must be matched to unlock the door.

Select a node and then select an organ to fill the connection between them with the organ's color. Two or more colors cannot connect to each other!

Solving this puzzle will reveal the Desecrated Relief behind the large door. The rare Blade of Oppressed Souls (which deals Psychic Damage) and a Waking Mind brain jar can also be found at the side.

Use the Waking Mind for a Permanent Buff

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Talking to the Slack-Skinned Head with the Waking Mind on the Mind-Archive Interface will give you an Illithid dialogue option to purge her mind.

Doing so will grant you the Githzerai Mind Barrier, a permanent condition that gives Advantage to Intelligence Saving Throws.

How to Get to the Necrotic Laboratory

Fight Ketheric Thorm

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Gaining access to the Necrotic Laboratory means gaining access to the Mind Flayer Colony.

The colony is part of Ketheric Thorm's boss fight in Act 2. You will have to enter the colony through the Hollow Tower hole right after Ketheric's first phase.

Once inside the colony, the Necrotic Laboratory at the southwest side of the map. It can be accessed by going at the end of the first hallway, or going into the next room after the Morgue.

How to Beat Ketheric Thorm

Clear the Necrotic Laboratory of Enemies

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Be prepared to fight as you will encounter Zombies, Winged Horrors, and Death Shepherds within the laboratory.

It is a good idea to prioritize the Death Shepherds when they get near you at the start of battle since they will prioritize reviving their dead allies.

Undead enemies are weak to Radiant Damage. Having a Cleric or a Paladin would be a good idea in this situation!

Explore the Mind-Archive Interface

Mind-Archive Location
Necrotic Library
(Mind Flayer Colony)
X: 695, Y: -116
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You can find the Mind-Archive Interface at the bottom-left of the laboratory. Use Jump or a similar action to cross the gap, then interact with the device.

The interface allows you to insert a green brain jar containing a Mind that communicates through the Slack-Skinned Head. You can use any jar you find throughout the colony (and even the ones you took from the Nautiloid at the beginning of the game.)

Each mind will have its own unique dialogue options. You will want to look out for the Waking Mind found behind the brain puzzle for the option to get a permanent buff to your Intelligence Saving Throws.

Baldur's Gate 3 Related Guides

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List of All Side Quests

Prologue Side Quests

All Prologue Side Quests
How to Free the Intellect Devourer How to Free Shadowheart

Act 1 Side Quests

Druid's Grove Quests

Druid Grove Quests
How to Steal the Sacred Idol Should You Save The Goblin Sazza? How to Avoid Tiefling Pickpockets
Save the Refugees How to Save Nadira How to Save Mirkon
How to Save the First Druid Halsin How to Open the Stone Slab Request Help from Nettie
How to Investigate and Expose Kagha Save Arabella -

The Risen Road Quests

The Risen Road Quests
Find the Missing Shipment How to Rescue the Grand Duke
Rescue the Trapped Man How to Free Oskar Fevras

Blighted Village Quests

Blighted Village Quests
How to Beat the Goblins: Blighted Village How to Open the Necromancy of Thay How to Recruit the Ogres
How to Finish the Masterwork Weapon That Barn: Avoid Killing Buthir Rescue the Gnome and Stop the Windmill

Goblin Camp Quests

Goblin Camp Quests
How to Get Volo's Ersatz Eye Defiled Temple Puzzle
Find the Nightsong Ask the Goblin Priestess for Help

Nautiloid Crash Region Quests

Nautiloid Crash Region Quests
Dank Crypt Guide The Dying Mind Flayer Auntie Ethel Quest Guide
How to Get Owlbear Cub Spiderling Nest Guide- How to Open the Selunite Chest
How to Get Scratch Should You Heal Pandirna Underground Passage Guide

Underdark Quests

Underdark Quests
Arcane Tower Guide Defeat the Duergar Intruders Save the Grymforge Gnomes
Find the Adamantine Forge Deliver Nere's Head How to Find the Mushroom Picker
How to Cure the Poisoned Gnome Help the Cursed Monk Omeluum Location

Mountain Pass Quests

Mountain Pass Quests
Steal a Githyanki Egg How to Beat Gremishkas How to Access Guardian of Faith Room
Dawnmaster Puzzle Guide Where to Find the Githyanki Creche -

This section is currently under construction. Check back later for updates!

Act 2 Side Quests

Last Light Inn Quests

Last Light Inn Quests
Seek Protection from the Shadow Curse Rescue the Tieflings Rescue Wulbren
How to Lift the Shadow Curse: Where to Find Thaniel Find Zevlor Help He Who Was
Investigate the Selûnite Resistance - -

Gauntlet of Shar Quests

Gauntlet of Shar Quests
Gauntlet of Shar: All Trials and Umbral Gems Kill Raphael's Old Enemy

Mind Flayer Colony Quests

Mind Flayer Colony Quests
How to Solve the Necrotic Laboratory

Act 3 Side Quests

Rivington Quests

Rivington Quests
Investigate the Suspicious Toys Solve the Open Hand Temple Murders Find the Missing Letters
How to Get to Wyrm's Rock Fortress How to Find Dribbles the Clown -

Lower City Quests

Lower City Quests
How to Get to the House of Hope How to Get to Cazador's Palace Rescue Orin's Victim
Aid the Underduke How to Get to the House of Grief Investigate the Murders

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