pf2e.fyi
From Pathfinder Bestiary 2, which isn't enabled.

Chernobue

CREATURE 12
UNCOMMONLARGECHAOTICEVILFIENDQLIPPOTHUNHOLY

The chernobue infects all creatures it encounters with itself, spreading pain and calamity wherever it flops and writhes. It sheds ruin and sups on anguish, but a chernobue can sometimes be persuaded to pause for a few moments of conversation if its partner in discourse can keep its attention by providing enough atrocious details. Resembling a tumor-like growth of oily blackness, this vile monstrosity has numerous muscular tentacles, a single glaring baleful eye, and a drooling, toothy maw in the middle of its body.

Perception +25; greater darkvision, scent (imprecise) 30 feet
Languages Chthonian; telepathy 100 feet
Skills Acrobatics +22, Athletics +25, Intimidation +25, Occultism +22
Str +7, Dex +4, Con +5, Int +4, Wis +7, Cha +5
Greater Darkvision

A creature with greater darkvision can see perfectly well in areas of darkness and dim light, though such vision is in black and white only. A creature with greater darkvision can see through even forms of magical darkness.

Telepathy 100 feet (aura, magical)

A monster with telepathy can communicate mentally with any creatures within the listed radius, as long as they share a language. This doesn't give any special access to their thoughts, and communicates no more information than normal speech would.

Constant Spells

A constant spell affects the monster without the monster needing to cast it, and its duration is unlimited. If a constant spell gets counteracted, the monster can reactivate it by spending the normal spellcasting actions the spell requires.

AC 33; Fort +23, Ref +18, Will +25
HP 220; Immunities controlled, fear effects; Resistances mental 10, physical 10 (except cold iron)
Aura of Order's Ruin (aura, occult)

30 feet. A lawful or good creature that begins its turn in this aura's emanation must attempt a DC 29 Will save or become Sickened 1 (lawful good creatures instead become Sickened 2).

Boiled by Light

A chernobue takes 2d10 fire damage each time it starts its turn in an area of bright light.

Recall Venom
Trigger A creature within 30 feet suffers the effects from stage 2 of rupturing venom
Effect The chernobue calls out telepathically to the semi-alive toxin, causing it to burst out of the target's body and slither through the air to drain back into one of the chernobue's mouths. The poisoned creature takes 7d6 bludgeoning damage (DC 32 basic Fortitude save) as the venom exits its body, but is thereafter cured of rupturing venom, and the chernobue regains an equal number of Hit Points.
Speed 30 feet
Melee Jaws +26 (magical, unarmed, unholy), Damage 3d10+13 piercing plus 1d6 spirit plus Rupturing Venom
Melee Tentacle Mouth +26 (agile, chaotic, magical, reach 15, unholy), Damage 3d6+13 piercing plus 1d6 spirit
Occult Innate Spells DC 32, attack +22; 7th Plane Shift (Self only); 6th Phantasmal Calamity, Phantom Pain; 5th Subconscious Suggestion; 4th Darkness (At will); Cantrips (6th) Daze, Detect Magic; Constant (4th) Air Walk
Paralyzing Display (concentrate, emotion, fear, incapacitation, mental, occult, visual)

The chernobue's eye pulses and its lid peels back to reveal mind-bending awfulness. Creatures in a 30-foot emanation must attempt a DC 32 Will save, after which they are temporarily immune to further Paralyzing Displays for 1 minute.

Critical Success The creature is unaffected.

Success The creature is Slowed 1 for 1 round.

Failure The creature is Paralyzed for 1d4 rounds. It can attempt a new save to end the effect at the end of each of its turns.

Critical Failure As failure, but paralyzed for 1 minute.

Rupturing Venom (poison)

The thick, orange venom injected by a chernobue is semi-alive, and as it seethes in a creature's body, it deals poison damage in addition to bludgeoning damage as it ruptures flesh

Saving Throw DC 32 Fortitude
Maximum Duration 6 rounds
Stage 1 2d6 poison plus 2d6 bludgeoning (1 round)
Stage 2 2d6 poison, 2d6 bludgeoning, and Enfeebled 2 (1 round)
Pathfinder Bestiary 2OGL