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

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

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

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

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

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

List of All Side Quests

Prologue Side Quests

Act 1 Side Quests

Druid's Grove Quests

The Risen Road Quests

Blighted Village Quests

Goblin Camp Quests

Nautiloid Crash Region Quests

Underdark Quests

Mountain Pass Quests

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

Act 2 Side Quests

Last Light Inn Quests

Gauntlet of Shar Quests

Mind Flayer Colony Quests

Act 3 Side Quests

Rivington Quests

Lower City Quests