Adult Insula

Obsessive Bond. The creature that is the source of the obsession that created in Insula is Charmed by it. The effect ends if the Insula dies or a remove curse spell is cast on the creature or the object.

Spider Climb. The Insula can climb difficult surfaces, including upside down on ceilings, without needing to make in ability check.

Unseen Entity. The Insula is Invisible and cannot be heard. If a creature succeeds on a DC 17 Wisdom (Perception) check it perceives the Insula beyond this invisibility. A creature charmed by the Insula automatically fails this check.

Multiattack. The Insula makes two attack with its claws.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one large or smaller creature. Hit: 12 (2d8 + 3) slashing damage. Instead of dealing damage, the Insula can grapple the target.

Proboscis. Melee Weapon Attack: +7 to hit, reach 5 ft., one large or smaller incapacitated humanoid or humanoid grappled by the Insula. Hit: 30 (5d10 + 3) piercing damage and the creature must succeed on a DC 17 Wisdom saving throw or become stunned until it finishes a short or long rest or a lesser restoration spell is cast on it.
As an action on subsequent turns, the Insula can deal 11 (2d10) psychic damage to a stunned creature it has grappled, regaining a number of hit points equal to the psychic damage dealt. If the Insula uses its action to do anything other than this, the creature can remake the saving throw at the end of the Insula's turn, ending the Stunned condition on a success.