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Ostinato

Medium · Aberration · CR 4 · Chaotic Neutral

Source. Tome of Beasts 1 (2023 Edition)

39 (6d8 + 12)

Ability Scores

Core attributes and their modifiers.

STR

-5

DEX

CON

INT

-3

WIS

CHA

Overview

Category Monsters

Size Medium

Type Aberration

Alignment Chaotic Neutral

XP 1100

Initiative Bonus +5

Movement

Walk 50 ft (15.2 m)

Swim 25 ft (7.6 m)

Climb 25 ft (7.6 m)

Crawl 25 ft (7.6 m)

Senses

Darkvision 60 ft (18.3 m)

Passive Perception 13

Skills

Perception +3

Languages

understands Common but can't speak, telepathy 120.0 ft (36.6 m).

Resistances & Immunities

Damage Immunities

poison

Damage Resistances

acid, cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks

Damage Vulnerabilities

thunder

Condition Immunities

charmed, exhaustion, grappled, paralyzed, petrified, poisoned, prone, restrained

Traits

Incorporeal Movement

The ostinato can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Invisibility

The ostinato is invisible.

Magic Resistance

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

Actions

Aural Symbiosis

Recharge 6

One Humanoid that the ostinato can see within 5 feet of it must succeed on a DC 13 Charisma saving throw or the ostinato merges with the target, becoming an enjoyable, repetitive tune in its host's mind. The ostinato can't be targeted by any attack, spell, or other effect, and it can't attack. The host retains control of its body and is aware of the ostinato's presence only as a melody, not as a living entity. The host no longer needs to eat or drink, gains the ostinato's Magic Resistance trait, and has advantage on Charisma checks. In addition, the host has disadvantage on Wisdom saving throws, and it can't maintain concentration on spells or other effects. At the end of each long rest, the host can make a DC 13 Wisdom (Insight) check, realizing that the music it hears comes from an external entity on a success.

Cacophony Burst

+7 to hit, range 60 ft (18.3 m). Hit: 3d8+3 thunder damage.

Melee or Ranged Spell Attack: +7 to hit, range 60 ft., one target. Hit: 16 (3d8 + 3) thunder damage.

Contagious Tune

1/day

While merged with a Humanoid host, the ostinato fills the minds of nearby creatures with the same catchy tune playing in its host's mind. Each creature within 30 feet of the ostinato's host must make a DC 13 Charisma saving throw, taking 21 (6d6) psychic damage on a failed save, or half as much damage on a successful one. The ostinato then gains temporary hp equal to the single highest amount of psychic damage dealt. A deafened creature is immune to Contagious Tune.

Multiattack

The ostinato makes two Cacophony Burst attacks.

About Ostinato

Ostinato is a medium aberration with a Challenge Rating of 4. It has a chaotic neutral alignment.

In combat, this creature maintains an Armor Class of 15 and possesses 39 hit points (derived from 6d8 + 12).

Ostinato has communication capabilities including understands Common but can't speak, telepathy 120 ft.. This allows it to interact verbally with various creatures and characters.

GM Tips: Using Ostinato

2 tips available

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

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.
Incorporeal Movement: This creature can pass through objects and walls! Use 'Magic Circle', 'Forcecage', or other magical barriers. Physical obstacles are ineffective.

Player Guide: Facing Ostinato

2 strategies available

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

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.
Hit Incorporeal Creature: This creature can pass through objects! Use magical weapons or spells. Physical attacks may not work. 'Magic Missile' or 'Spiritual Weapon' are effective.

Encounter Building Calculator

Standard Party Encounter (4-5 characters):

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

Solo Encounter:

A single character of level 6 (up to level 20) can face this creature in a medium to hard encounter.

Experience Point Thresholds:

Medium: 2,000 XP
Hard: 3,000 XP
Deadly: 4,000 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 Ostinato?: Ostinato has a Challenge Rating of 4, making it appropriate for parties of level 4.0.
What type of creature is Ostinato?: Ostinato is a Medium Aberration, which affects how certain spells and abilities interact with it.
What languages does Ostinato speak?: Ostinato can communicate in understands Common but can't speak, telepathy 120 ft..