Corrupted Brain

Creature Sense. The corrupted elder brain is aware of the presence of creatures within 5 miles of it that have an Intelligence score of 4 or higher. It knows the distance and direction to each creature, as well as each one’s Intelligence score, but can’t sense anything else about it.

Paranoia. Creatures wthin 5 miles of a corrupted brain feel as if they are being followed, even when they’re not.  Each affected creature must make a Wisdom saving throw (DC12) or begin to feel paranoid and fearful.  (Those who fail this roll will have a -3 to their initiative rolls for 12 hours)

Magic Resistance. The corrupted elder brain has advantage on saving throws against spells and other magical effects.

Hover.  The corrupted elder brain is in a constant state of hovering.  Should anything cause the brain to lose consciousness, or any effect that would cause another creature to fall prone would simply cause the creature to pause and remain stationary until its next turn.  Only upon death will a corrupted elder brain fall and actually touch the ground.

Spellcasting. The corrupted elder brain is a 7th-level spellcaster. Its innate spellcasting ability is Intelligence (spell save DC 16, +7 to hit with spell attacks). The corrupted elder brain has following spells prepared, requiring no spell components:

• Cantrips (at will): message, mind sliver, eldritch blast
• 1st level (5 slots): charm person, shield, thunderwave
• 2nd level (4 slots): blindness/deafness, suggestion
• 3rd level (3 slots): counterspell, fear, slow

Telepathic Eavesdropping. The elder brain can overhear any telepathic conversation within 5 miles of it. The creature that initiated the telepathic conversation makes a DC 18 Wisdom saving throw when telepathic contact is first established. If the save is successful, the creature is aware that something is eavesdropping. The nature of the eavesdropper isn’t revealed.

Detect Thoughts.  The corrupted elder brain can sense the presence of thoughts within 30 feet of itself that belong to creatures that know languages or are telepathic. It cannot read the thoughts, but it knows that a thinking creature is present.  The ability is blocked by 1 foot of stone, dirt, or wood; 1 inch of metal; or a thin sheet of lead.

Communication.  If a creature has an intelligence higher than 6, the corrupted elder brain can communicate with it through telepathy.

Multiple Attacks. The corrupted brain can make 2 tentacle attacks against the same or two different targets that are in range per round.  In addition to these, it can Sense the Thoughts of a target it is not attacking.

Sense Thoughts. The elder brain targets a creature with which it has a psychic link. The elder brain gains insight into the target’s emotional state and foremost thoughts (including worries, loves, and hates).

Tentacle Attack. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 6 (1d6 + 2) acid damage.  A creature struck by this attack must make an Intelligence saving throw (DC14) or suffer an additional 5 (2d4 + 2) psychic damage. 

Failing the saving throw, they must make an additional dexterity saving throw (DC16) or they will become grappled.  The corrupted brain can grapple up to 6 creatures at a time.  While grappled, a creature will take continuing psychic damage until they free themselves.  A grappled creature may make an intelligence saving throw (DC16) to free themselves of the grapple at the end of their turn.  A creature reduced to 0hp while grappled will have disadvantage on death saving throws and will be absorbed into the corrupted brain should they die.  A creature who dies this way can never be revived.

Spellcasting.  As a bonus action, the corrupted brain can cast any of its known spells, even if they are not specific to bonus actions.

Psychic Backlash. When the corrupted brain takes damage, it can respond to the attack with a psychic backlash against their attacker as long as they are 60' or less away.  The creature that damaged the corrupted brain is momentarily surrounded by an aura of eldritch energies.  It makes an Intelligence saving throw (DC14), taking 5 (2d4 + 2) psychic damage on a failing roll.

Legendary Resistance (3/Day).   If the corrupted elder brain fails a saving throw, it can choose to succeed instead.