b'Seaweed Siren \n'b'\n'b'  Large   monstrosity ,  unaligned  \n'b'  Armor Class  18 (natural armor) \n'b' Hit Points  294 (28d10+140) \n'b' Speed  30 ft., swim 30 ft.\n'b' STATS STR: 29 (+9) DEX:  16 (+3)  CON:  20 (+5)  INT:  11 (+0)  WIS:  16 (+3)  CHA:  21 (+5)  \n'b'\n'b'\n'b'\n'b'\n'b'\n'b'\n'b'  Saving Throws   Str  +14,  Con  +15,  Wis  +13,  Cha  +13 \n'b' Skills   Athletics  +14,  Deception  +15,  Perception  +13,  Stealth  +13 \n'b' Damage Resistances  fire; bludgeoning, piercing, and slashing from nonmagical attacks \n'b' Damage Immunities  acid, cold \n'b' Condition Immunities   charmed ,  frightened  \n'b' Senses   darkvision  120 ft., passive  Perception  23 \n'b' Languages  Aklo \n'b' Challenge  17 (18,000 XP) \n'b' Special Traits \n'b'\n'b'  Cacophony . The seaweed siren projects a constant noise that disrupts spellcasting. Any creature casting a spell within 100 feet of the seaweed siren requires a DC 19  Constitution  saving throw. Failure means the spell fails to be cast. The action is used, but any spell slots or uses per day are not. In addition, any hearing-based perception checks made within 100 feet of the seaweed siren have disadvantage. The seaweed siren can use its bonus action to stop using this ability, or to reactivate it. \n'b'  Innate Spellcasting . The seaweed siren\xe2\x80\x99s spellcasting ability is  Charisma  (spell save DC 18). It can innately cast the following spells, requiring no material components: \n'b'\n'b'  At will :  suggestion ,  tongues ,  minor illusion  \n'b'  1/day each :  bestow curse , dominate,  irresistible dance  \n'b'\n'b'  Multi-Headed . While the seaweed siren can see in all directions, and has advantage on  Wisdom  ( Perception ) checks, which applies to its passive  Perception  score. It also has advantage on saving throws against being  blinded ,  deafened ,  stunned , and knocked  unconscious . Whenever the seaweed siren takes 40 or more damage in a single turn, one of its heads dies. If all three heads die, the seaweed siren can no longer use its Cacophony ability, or its innate spellcasting. Heads regrow at a rate of one per day. \n'b'  Water Breathing . The seaweed siren cannot breathe air. It can move on land but must hold its breath. \n'b'\n'b' Actions \n'b'\n'b'  Multiattack . The seaweed siren makes three bite attacks. \n'b'  Bite .  Melee Weapon Attack : +9 to hit, reach 5 ft., one target.  Hit : 20 (2d10 + 9) piercing damage and 11 (2d10) poison damage. \n'b'  Sonic Beam (Recharge 4-6) . The seaweed siren uses its heads to create a wail that affects everything in a 60-foot line. Each creature in that line must make a DC 18  Constitution  saving throw, taking 56 (12d8) thundering damage and becoming  deafened  on a failed save, or half as much damage and not becoming  deafened  on a successful one. \n'b'\n'b' About \n'b' Seaweed sirens hunt near the shore, where they wait for clam diggers strolling the beaches, lone fisherfolk, or even passing ships. The creature\xe2\x80\x99s three singing heads sway atop serpentine necks that extend from a bulbous body split by a wide, toothy mouth. Pungent strands of seaweed  cover  the creature like slimy hair. Once a seaweed siren spots its prey, the creature lurks just under the water and allows its three strange heads to protrude above the surface. These heads are nothing more than appendages, and while it can breathe through them it doesn\xe2\x80\x99t use them to eat. Seaweed sirens\xe2\x80\x99 heads grow differently depending on where the creature developed in order to match the skin tone and apparent ethnicity of the surrounding humanoid population. In addition, the heads are eyeless\xe2\x80\x94 the siren sees using the many eyes on its main body mass. A seaweed siren stands over 8 feet tall from the tip of its stubby legs to the top of its heads and is nearly 7 feet in diameter. The creature weighs upward of 3,500 pounds. \n'b'  Horrific Hybrid . At first glance, this creature appears to  blur  the line between plant and animal. Three eyeless heads sway above the central body mass, constantly singing, chanting, and speaking in nonsense languages and simple babble. Seaweed covers the creature\xe2\x80\x99s three false heads and its main central body\xe2\x80\x94a form of camouflage to  help  the beast remain hidden while hunting. Six stout, crablike legs carry this creature along the coast and through the rocky tide pools it inhabits. \n'b'  Entrancing cacophony . The seaweed siren\xe2\x80\x99s heads sing songs and babble in strange nonsense languages to fuel the seaweed siren\xe2\x80\x99s many special abilities. Even when not in use against a potential meal, the heads seemingly converse with each other, holding lengthy conversations full of random syllables and made-up words. Once it draws its prey near, the seaweed siren attempts to charm or bewilder its foe to gain the advantage. After this, the creature moves closer and begins to devour its still-living victim. While the seaweed siren prefers to dine on living humanoids, it uses its strident squall attacks to incapacitate or kill prey that flees or resists its charm attempts. \n'b' Seaweed sirens sometimes ally themselves with other aquatic creatures to share in hunts or for mutual protection.  Sahuagin  typically don\xe2\x80\x99t trust them but may ally with them long enough to capture new slaves and restock their humanoid food supply. Locathah sometimes use these strange beasts as protectors, keeping them well fed in return for the creatures serving as lookouts and sentinels.  Merfolk  and aquatic elves avoid seaweed sirens, and even go so far as to sometimes warn other humanoid communities when one is discovered to be hnting nearby. \n'b' Seaweed sirens use a form of aggressive mimicry, appearing to have humanoid features in order to lure in their preferred meals. They can converse in Aklo, and constantly babbles in glossolalia, but if it manages to talk with another sentient being that has a language long enough, it begins mimicking the other\xe2\x80\x99s language and speech patterns, eventually sounding exactly like it. Though a seaweed siren can use its  tongues  spell to understand and speak any language, it prefers to talk with and  mimic  its conversational partners without resorting to using this ability. Some speculate the creature catalogs every conversation in order to add to the collection of sounds and words that power its cacophony special ability.'