Alluvium Eldritch Coagulant

Covered in a thin, cracked skin reminiscent of congealed fat atop cold stew an eldritch coagulant rivals some subterranean lakes in size. This gristle resembles a vast mirror of broken sea glass. Huge pseudopods breach the surface now and again, caressing the cavern ceiling and walls and leaving acid-polished stone behind. This glass-like surface reflects the coagulant’s sickly, pulsating radiance which only intensifies whenever a sapient creature draws near. The murk beneath the ghastly surface is a gangrenous blue-green but disturbingly emits no odor. While it is unknown what language the fragment speaks those it telepathically communicates with describe its voice as warm and fatherly, as well as comprehensible. That is, of course, if the brush of minds does not drive the mortal creature mad.

Deathless Debris. A scrap of an elder evil's essence an eldritch coagulant carries within it a mere sliver of the devoured cosmic horror's power. Yet, even this minuscule amount is enough to keep the perpetually festering flesh alive. IF even a scrap of the ooze's body remains after it has been vanquished the terror will regenerate, but a rate so slow that dozen's of mortal lifespans will pass before it is large and powerful enough to be a threat once again.

Lonely and Loathesome. The eldritch coagulant is driven by an acute fear of being alone more than mere malevolence, though the depths of its evil are still unfathomable. The abomination knows it is but a fragment of a whole and believes by absorbing and transforming sapient species it can claw its way back to that zenith. With each new sacrifice dissolved the mad whispers of their minds lull the ooze's anxiety with their constant noise. It views the alluvium of its colony as both an extension of itself and a loyal family that will never forsake it. The eldritch coagulant coaxes all those it meets to join its family and ruthlessly destroys those they believe threaten it.

Eldritch Coagulant

Gargantuan Ooze, neutral evil

Armor Class 7

Hit Points 174 (12d20 + 48)

Speed 0ft

Str 21 Dex 5 Con 19 Int 16 Wis 13 Cha 19

Saving Throws. Int +8, Wisdom +6

Damage Immunities acid, cold, slashing

Damage Resistances necrotic

Condition Immunities charmed, exhaustion, petrification, prone

Senses blindvision 30ft, passive Perception 11

Languages All, Telepathy 120ft

Challenge 12 (8,400 XP)

Absorb

Whenever the creature enters the eldritch coagulant's space, the creature must make a DC 17 Dexterity saving throw. On a successful save, the creature can choose to be pushed 5 feet back or to the side of the ooze. A creature that chooses not to be pushed suffers the consequences of a failed saving throw.

On a failed save, the creature is absorbed by the eldritch coagulant, and the creature takes 12 (4d6) acid damage and is absorbed. The absorbed creature can't breathe, is restrained, and takes 21 (6d6) acid damage at the start of each of the ooze’s turns.

An absorbed creature can try to escape by taking an action to make a DC 17 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the ooze.

Amphibious

The eldritch coagulant can breath both air and water.

Magic Resistance

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

Blood Sense

The eldritch coagulant senses any creature with blood within 120ft.

Fetid Pool

The eldritch coagulant takes up its entire space. Other creatures can enter the space, but a creature that does so is subjected to the ooze’s Absorb ability and has disadvantage on the saving throw.

Creatures inside the eldritch coagulant can be seen but have total cover.

A creature within 5 feet of the ooze can take an action to pull a creature or object out of the cube. Doing so requires a successful DC 17 Strength check, and the creature making the attempt takes 12 (4d6) acid damage.

The eldritch coagulant can hold only one huge creature, up to four large creatures, or up to eight Medium or smaller creatures inside it at a time.

Timeless Intelligence

The Eldritch Coagulant is always under the effects of the Comprehend Languages spell. Any creature that telepathically communicates with the ooze automatically is under the effects of the Tongues spell.

Actions

Multiattack

The eldritch coagulant makes two pseudopod attacks as one action. It may also make one psychic harpoon attack as well, if available.

Pseudopod

Melee Weapon Attack: +9 to hit, reach 30 ft., one target. Hit: 12(4d6) acid damage. At the end of a minute, the creature must make a DC 14 Constitution save or take 7 (2d6) acid damage. This save is repeated every minute until the creature succeeds or dies. Creatures slain by the pseudopod attack or its repeated damage spawn a Grey Ooze in the corpse's square.

Psychic Harpoon

Ranged Spell Attack: +8 to hit, ranged 60ft., one target. Hit: 12(4d6) psychic damage. The creature must make a DC 16 Charisma save or must use all its actions to move toward the eldritch coagulant but otherwise is considered stunned. At the end of each turn, the creature may repeat the save, effect ending on success. Only one creature may be under the effect of a psychic harpoon at a time.

Legendary Actions

The eldritch coagulant can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The eldritch coagulant regains spent legendary actions at the start of its turn.

Lash (1 point): The eldritch coagulant makes a pseudopod attack.

Mental Binding (2 points): The eldritch coagulant can try to paralyze a creature within 60 ft. The ooze makes a Charisma check contested by the creature's Strength check. If the ooze wins the contest, the creature is paralyzed until the start of the eldritch coagulant’s next turn, at which point the effect ends. The eldritch coagulant cannot use psychic harpoon while Mental Binding is active.

Psychic Drain (2 points): Tne creature absorbed by the eldritch coagulant takes 10 (3d6) psychic damage, and the eldritch coagulant regains hit points equal to the damage the creature takes.

Lair Actions

On initiative count 20 (losing initiative ties), the eldritch coagulant can take a lair action to cause one of the following magical effects; the lich can’t use the same effect two rounds in a row:

The eldritch coagulant communicates telepathically with a creature within 60ft and fills its head with a rush of sanity-fraying knowledge. The creature must succeed on a DC 16 Charisma save or suffer Madness, as per the DMG with the following effects:

1- "I can feel my bones, they want out."

2- "Chewing food is disgusting. I will only swallow food whole."

3- "I am so lonely. I need others around me at all time."

4- "My wounds are best left to fester."

The eldritch coagulant targets one creature it can see within 30 feet of it. The creature is coated in corrosive slime and must succeed on a DC 14 Constitution save at the beginning of each of its turns or take 2d6 acid damage, and its armor loses 1 AC being destroyed when it reached AC 10. Once the creature succeeds on the save the effect ends. Creatures slain by this repeated damage spawn a Grey Ooze in the corpse's square.

The eldritch coagulant summons up the psychic afterimage of humanoids sacrificed to it, coalescing in a Weeping Conscript . The creature appears in an unoccupied square adjacent to the eldritch coagulant and acts in initiative 20. The eldritch coagulant cannot use this lair ability again until the weeping conscript is dead.

Regional Effects

The true natural of alluvium humanoids within the lair and above are obscured and they appear as normal members of their original races. This is an illusionary effect that cannot be dispelled. Creatures immune to illusionary effects or with True Sight see the devolved humanoids as they are.

Food in the area quickly spoils and is reduced to a sludge-like paste.

Unsettling, unintelligible whispers tease the edge of one's hearing now and again.