Brain Leech
Medium monstrosity, unalignedArmor Class 15 (natural armor)
Hit Points 93 (11d8 + 44)
Speed 30 ft., swim 20 ft.
| STR | DEX | CON | INT | WIS | CHA |
|---|---|---|---|---|---|
| 17 (+3) | 8 (-1) | 19 (+4) | 2 (-4) | 14 (+2) | 4 (-3) |
Skills Perception +4
Damage Resistances bludgeoning
Condition Immunities charmed
Senses tremorsense 30 ft., passive Perception 14
Languages —
Challenge 4 (1,100 XP)
Amphibious. The brain leech can breathe air and water. Multiattack. The brain leech makes two attacks, only one of which can be a slurp brains attack.
Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) piercing damage, and the target must succeed on a DC 14 Constitution saving throw or be poisoned for 1 minute. While poisoned, the target is restrained as its limbs grow heavy and sluggish. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Slurp Brains. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature that is incapacitated or restrained. Hit: 12 (2d8 + 3) piercing damage and the leech attaches to the target. While attached, the brain leech doesn’t attack. Instead, at the start of each of the leech’s turns, the target’s Intelligence score is reduced by 1d4 as the leech feeds on the creature’s psychic energy. The target dies if this reduces its Intelligence to 0. If the target dies, the leech cracks open the target’s brain case and slurps up the creature’s brain. Otherwise, the reduction lasts until the target finishes a short or long rest.
The brain leech can detach itself by spending 5 feet of its movement. It does so after it has reduced the creature’s Intelligence by 12 or if the target dies. Once the leech has drained a total of 12 Intelligence from any number of creatures, it can’t slurp the brains of another creature and it gains three levels of exhaustion. A creature, including the target, can take its action to detach the leech by succeeding on a DC 13 Strength check.
Trill (Recharge 4-6). Each creature within 30 feet of the brain leech must succeed on a DC 12 Wisdom saving throw or be incapacitated 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. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the leech’s Trill for the next 24 hours.