Whisper Hint. when you enter area the gluttonous soul area you will hear constant whispering sounds and most of them telling you to be quiet

Covered in Mist. the gluttonous soul is always heavily obscured unless your underneath it where it's lightly obscured

Sound Reactant Mist. the gluttonous soul produces a special water like mist that is completely harmless when inhaled in gas form, but it is a gas when it is interacting with sound that is less than 35 dB of sound, if the mist encounters a sound more than 35 dB of sound it will turn into a liquid and if the mist has been inhaled by a creature they take 4d8 necrotic damage and make a dc 15 constitution saving throw if you if you fail you take 2d8 necrotic damage for 3 rounds and each round the creature has this affect it increases 2 more rounds, begin to suffocate and have to retry the save, if you fail by five you scream and make 120 dB of sound, if you succeed you don't make any sound and fall to the ground prone and you aren't suffocating, if the mist interacts with 100 dB of sound it turns into a solid and if the mist was inhaled by a creature they take 3d8 necrotic damage and 2d6 piercing damage for 6 rounds and each round this creature stays in this affect the affect round increases by 2 rounds, begin to suffocate and make a dc 19 constitution saving throw if you fail you take 6d6 necrotic damage and have to retry the save, if you fail by 9 you go unconscious and alert the creature to where you are, if you succeed you make enough sound to turn the mist into a liquid.

if you cast silence all sound mist will turn into a burning ball of plasma any creature within 20 ft of the flaming gas must make a dc 17 dexterity saving throw or take 20(5d8) fire damage, half as much damage on a success. if the the gluttonous soul encounters a thunderclap like spell it must make a dc 17 dexterity saving throw or be immediately grounded(any any creature bellow it will take the falling damage) and buried in it's mist that has turned into snow on a fail but it is given an ac of 23 and non of it's attacks are hindered, if it decides to arise it must make a dc 20 strength check and if it succeeds it flies out of the snow not heavily obscured by it's mist for 1 minute. if it succeeds it takes half the damage

Hovering. the gluttonous soul hovers 20 ft off the ground, but the gas extends an extra 10 ft away from it, and if it is falls it will fall to the ground dealing 35 (7d10) bludgeoning damage to any creature under it. creatures can walk underneath the thing with relatively no harm

Blind. the gluttonous soul will attack you if you make a sound over 40 dBs 3 times, or a more than 100 dB sound once. if you haven't made a sound past those thresholds it has disadvantage on attacking you. the thing get irritate by things that make over 140 dBs of sound but it will willingly go over the thing if there is food on the other side.

Mysterious Fear. The mere sight of a gluttonous soul is enough to overwhelm even the most hardened warriors with fear. A creature who sees a thing while within 1 mile of it must succeed on a DC 18 Wisdom saving throw or be frightened of the thing for 1d4 rounds. if A creature fails by 8 or more they are frightened but also paralyzed. Whether or not the save is successful, that creature cannot be affected again by that same thing's fear trait for 24 hours.

Hunger for Flesh. when a gluttonous soul eats 10 pounds of flesh it heals 20 hp, if a creature dies to the swallow attack 50% of their weight will be the amount of flesh the thing gets from the creature. if it's healing exceeds the thing's max hp it will take half of the hp it healed and turn it into temporary hp. any creature that is killed by a gluttonous soul's swallow action is given a choice to ether let go of their body or hold onto their body, if they decide to let go of their body they will travel to the after life, if they decide to hold onto their body they must succeed on a dc 20 wisdom saving throw and if they succeed when the gluttonous soul dies they will turn into a docile zombie that has the fragmented personality and memories of the original creature and on a fail you can go to the after life or turn into a docile cr 4 or less incorporeal undead that has the same personality and memories of the original creature.

Reviving Heart. when the gluttonous soul is killed the gluttonous soul will disintegrate and  what is left is 1d8 docile zombie that has the fragmented personality and memories of the original creature and a large heart shaped flesh sphere will remain, it has 20 hp, and is immune to all damage types except for radiant and if the heart is left alone for 1d4 weeks at the end of that time the heart will be able to move and consume flesh and after enough consumption it can reform into a gluttonous soul.

Bone Spots. when a creature is attacking the gluttonous soul they must roll a d8 on a 1-7 nothing happens but on a 8 the gluttonous soul has a armor call of 17 against that attack, this dose not apply if the creature has advantage on the gluttonous soul

Tentacle. Melee Weapon Attack: +5 to hit, range 25 ft. Hit: 10 (2d6 + 3) bludgeoning damage. If the target is a creature, it is grappled (escape DC 19). Until this grapple ends. every round a creature is moved 1d10 ft toward the thing's mouth.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft. Hit: 16 (5d6 + 2) piercing damage.

Swallow. The gluttonous soul makes one bite attack against a huge or smaller creature it is grappling. If the attack hits, the target takes the bite’s damage, the target is swallowed, and the grapple ends. While swallowed, the creature is Blinded and restrained, it has total cover against attacks and other effects outside the gluttonous soul, and it takes 15 (3d10) acid damage and 15 (3d10) piercing damage at the start of each of the things turns.

If the thing takes 30 damage or more on a single turn from a creature inside it, the thing must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone right underneath it. If the gluttonous soul dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 30 feet of movement, exiting prone.

Tongue(5/6). Melee Weapon Attack: +5 to hit, range 30 ft(from the thing's mouth). Hit: 16 (2d8 + 8) piercing damage. If the target is a creature, it is grappled (escape DC 21). after the save is done the thing dose a Swallow attack

Hallucination(3/day). the souls of the creatures the gluttonous soul ate begin to form into ghostly shapes underneath the things body, the thing casts confusion with no need for components and if you roll a 1-2 you will scream or it can cast Fear