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Crystalline Monolith

Huge · Aberration · CR 7 · Lawful Neutral

Source. Tome of Beasts 2

15 (natural armor)

123 (13d12+39)

Ability Scores

Core attributes and their modifiers.

STR

DEX

CON

INT

WIS

CHA

Overview

Category Monsters

Size Huge

Type Aberration

Alignment Lawful Neutral

XP 2900

Initiative Bonus +0

Movement

Fly 30 ft (9.1 m)

Hover Yes

Senses

Blindsight 120 ft (36.6 m)

Passive Perception 16

Skills

Arcana +7 History +7 Insight +6 Nature +7 Perception +6

Languages

Deep Speech, Undercommon, telepathy 120.0 ft (36.6 m).

Resistances & Immunities

Damage Immunities

poison

Damage Resistances

cold, fire

Condition Immunities

blinded, paralyzed, petrified, poisoned, prone

Traits

False Appearance

While the crystalline monolith remains motionless, it is indistinguishable from a giant crystal.

Innate Spellcasting (Psionics)

The crystalline monolith’s innate spellcasting ability is Intelligence (spell save DC 15). It can innately cast the following spells, requiring no components:
At will: detect magic, detect thoughts, mage hand, silent image
3/day each: clairvoyance, hypnotic pattern, stinking cloud, telekinesis
1/day each: confusion, dominate person, suggestion

Magic Resistance

The crystalline monolith has advantage on saving throws against spells and other magical effects.

Powerful Mind

The crystalline monolith has advantage on Intelligence saving throws and ability checks.

Actions

Cast a Spell (Costs 3 Actions)

The crystalline monolith casts a spell from its list of innate spells, expending a daily use as normal.

Mind Spear

+7 to hit, range 30 ft (9.1 m). Hit: 4d6 psychic damage.

Ranged Spell Attack: +7 to hit, range 30 ft., one target. Hit: 14 (4d6) psychic damage.

Multiattack

The crystalline monolith makes two slam attacks or two mind spear attacks. If both slam attacks hit a Large or smaller target, the target must succeed on a DC 14 Constitution saving throw or begin to turn to crystal and be restrained. The restrained creature must repeat the saving throw at the end of its next turn, becoming petrified on a failure or ending the effect on a success.

Psychic Burst

Recharge 5–6

The crystalline monolith emits a burst of psychic energy in a 30-foot cone. Each creature in that area must succeed on a DC 15 Intelligence saving throw or take 28 (8d6) psychic damage and be stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Slam

+5 to hit, reach 10 ft (3 m). Hit: 2d8+2 bludgeoning damage.

Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 11 (2d8 + 2) bludgeoning damage.

Teleport (Costs 2 Actions)

The crystalline monolith magically teleports up to 120 feet to an unoccupied space it can see.

Legendary Actions

Cast a Spell

Cost 3

The crystalline monolith casts a spell from its list of innate spells, expending a daily use as normal.

Detect

Cost 1

The crystalline monolith makes a Wisdom (Perception) check.

Teleport

Cost 2

The crystalline monolith magically teleports up to 120 feet to an unoccupied space it can see.

About Crystalline Monolith

Crystalline Monolith is a huge aberration with a Challenge Rating of 7. It has a lawful neutral alignment.

In combat, this creature maintains an Armor Class of 15 and possesses 123 hit points (derived from 13d12+39).

Crystalline Monolith has communication capabilities including Deep Speech, Undercommon, telepathy 120 ft.. This allows it to interact verbally with various creatures and characters.

GM Tips: Using Crystalline Monolith

2 tips available

When using Crystalline Monolith in your D&D 5e campaign, consider these tactical approaches:

Flight Control Strategy: Target flying creatures with spells like 'Hold Person', 'Web', or 'Grease' to ground them. Without flight restriction, they can escape melee range easily. Consider area denial spells below their flight altitude to force them into disadvantageous positions.
Telepathic Communication: This creature can communicate telepathically, making it excellent for coordination with allies. Silence spells won't stop its communication. Consider 'Mind Blank' or abilities that block telepathy.

Player Guide: Facing Crystalline Monolith

2 strategies available

When your party encounters this creature, keep these strategies in mind:

Counter Flight Advantage: This creature can fly! Use ranged attacks, reach weapons, or spells like 'Thunderwave' to push it away. Consider 'Gust of Wind' or 'Earthbind' to ground it. Melee characters need fly speed or flight magic to engage.
Telepathy Awareness: This creature communicates telepathically! It can coordinate with allies silently. Silence won't stop it. Use 'Mind Blank' or abilities that block telepathy. Be cautious of mental attacks.

Encounter Building Calculator

Standard Party Encounter (4-5 characters):

This creature is a medium encounter for a party of 4 characters of level 7.

Solo Encounter:

A single character of level 10 (up to level 20) can face this creature in a medium to hard encounter.

Experience Point Thresholds:

Medium: 5,600 XP
Hard: 8,400 XP
Deadly: 11,200 XP

Based on D&D 5e Dungeon Master's Guide encounter building guidelines. CR roughly equals party level for medium encounters.

Frequently Asked Questions

What is the challenge rating of Crystalline Monolith?: Crystalline Monolith has a Challenge Rating of 7, making it appropriate for parties of level 7.0.
What type of creature is Crystalline Monolith?: Crystalline Monolith is a Huge Aberration, which affects how certain spells and abilities interact with it.
What languages does Crystalline Monolith speak?: Crystalline Monolith can communicate in Deep Speech, Undercommon, telepathy 120 ft..