_Huge Aberration, Lawful Evil_
**Armor Class** 15 (Natural Armour)
**Hit Points** 95 (10d12 + 30)
**Speed** 0 ft.
| STR | DEX | CON | INT | WIS | CHA |
| :-----: | :----: | :-----: | :-----: | :-----: | :-----: |
| 14 (+2) | 8 (-1) | 16 (+3) | 20 (+5) | 18 (+4) | 18 (+4) |
**Saving Throws** Con +6, Int +8, Wis +7
**Skills** Arcana +8, Insight +7, Perception +7
**Damage Resistances** Psychic
**Condition Immunities** Blinded, Charmed, Deafened, Frightened, Prone
**Senses** Blindsight 120 ft. (blind beyond this radius)
**Languages** Telepathy 5 miles
**Challenge** CR 7 (2,900 XP)
**Proficiency Bonus** +3
## Traits
### Hive Mind
While the Young Elder Brain is alive, allied Mind Flayers and Intellect Devourers within the hive have advantage on initiative rolls and cannot be surprised.
---
### Psychic Awareness
The Elder Brain automatically knows the location of every creature with an Intelligence score of 3 or higher within 120 feet.
Invisible creatures gain no benefit against this sense.
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### Immobile
The Young Elder Brain cannot move or be moved.
## Actions
#### Mind Spike
_Ranged Spell Attack:_ +8 to hit, range 120 ft., one target.
**Hit:** 18 (4d8) psychic damage.
#### Psychic Pulse _(Recharge 5–6)_
The Elder Brain emits a wave of psychic force.
Each creature of its choice within 30 feet must succeed on a **DC 15 Intelligence saving throw** or take **18 (4d8) psychic damage**.
On a successful save, the creature takes half damage.
#### Psychic Command
The Elder Brain targets one allied creature it can perceive within 120 feet.
That creature may immediately move up to its speed and make one weapon attack as a reaction.
### Lair Actions
On initiative count 20 (losing initiative ties), the Elder Brain takes one lair action. It cannot use the same lair action two rounds in succession.
#### Grasping Tendrils
Organic tendrils erupt from the floor.
Choose one 15-foot-square area.
Creatures in that area must succeed on a **DC 14 Strength saving throw** or become **Restrained**.
A restrained creature may repeat the saving throw at the end of each of its turns.
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#### Psychic Feedback
The hive lashes out: Choose one creature.
It must succeed on a **DC 15 Wisdom saving throw** or suffer **9 (2d8) psychic damage** and have disadvantage on the next attack roll it makes before the end of its next turn.
---
#### Nerve Surge
One Neural Node begins pulsing violently.
Until initiative count 20 of the next round, all creatures within 10 feet of that node treat the area as difficult terrain.
---
# Neural Nodes
The chamber contains **three Neural Nodes** connected to the Elder Brain.
Each Node has:
- **AC:** 13
- **HP:** 15
- Immunity to Psychic damage
Whenever a Node is destroyed:
- The Elder Brain immediately takes **10 psychic damage**.
- Its **Psychic Pulse** damage is reduced by **1d8**.
- The chamber shakes violently as the psychic network weakens.
When all three Nodes are destroyed:
- The Elder Brain loses access to **Psychic Pulse**.
- It can no longer use **Psychic Command**.
- Lair actions cease.