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

Web Sense. While in contact with a web, the abberettercap knows the exact location of any other creature in contact with the same web.

Abberative Web Walker. The abberettercap ignores movement restrictions caused by webbing, and it's movement speed is doubled while moving on webbing. 

Ichor-Slicked Membrane. The abberettercap ignores effects that would reduce it's movement speed, and always has advantage on dexterity checks and saving throws. 

Multiattack. The abberettercap makes two attacks: one with its bite and one with its claw-like ichor-slicked tentacle, either of which can be replaced with its web. 

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 6 (1d8 + 3) piercing damage plus 5 (1d8 + 3) poison damage. The target must succeed on a DC 13 Constitution saving throw or be poisoned for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Claw-like Ichor-Slicked Tentacle. Melee Weapon Attack: +5 to hit, reach 10ft., one target. Hit: 7 (2d4 + 3) bludgeoning damage, and the creature must succeed on a DC 13 dexterity saving throw, or have disadvantage on all of their ability checks, saving throws, and attacks until the end of their next turn. 

Web (Recharge 3–6). Ranged Weapon Attack: +6 to hit, range 30/60 ft., one Large or smaller creature. Hit: The creature is restrained by webbing. As an action, the restrained creature can make a DC 11 Strength check, escaping from the webbing on a success. The effect also ends if the webbing is destroyed. The webbing has AC 10, 5 hit points, vulnerability to fire damage, and immunity to bludgeoning, poison, and psychic damage.

Bloated Monstrosity. If the abberettercap starts its turn with 10 or less health remaining, it can choose to enter a seizure-like state before bursting, exploding into a mess of viscera and tar-like slime. All creatures within 40 feet of the abberettercap must succeed on a DC 13 dexterity saving throw, or get coated in the disgusting substance, becoming poisoned and frightened for the next 24 hours.