Bebilith

Legendary Resistance (2/Day). If bebilith fails a saving throw, it can choose to succeed instead.

Magic Resistance. The bebilith has advantage on saving throws against spells and other magical effects.

Magic Weapons. The  bebilith's  weapon attacks are magical.

Danger sense. The bebilith has advantage on all dexterity saves if it can see it coming 

Hunters sense. If a creature approaches the bebilith the bebilith can use the disengage action as a bonus action 

Spider Climb. The bebilith 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 bebilith knows the exact location of any other creature in contact with the same web.

Web Walker. The bebilith ignores movement restrictions caused by webbing.

Multi attack. The bebilith makes 3 attacks 1 with its venomous bite and 2 with its rending claws.

Rending claws. Melee Weapon Attack: +13to hit, reach 15 ft., 1 target. Hit: 16 (2d10 + 6) [slashing] damage and if the attack rolls is at least 5 higher than there ac then there armor gets a -1 penalty if it gets to -10 then there armor is destroyed, this effect doesn't effect armor of adimantine. 

Acidic bite. Melee Weapon Attack: +13 to hit, reach 5 ft., 1 target. Hit: 14 (2d8 + 6) [piercing] damage, The target must make a dc 20 con save or take 24 (6d8) acid damage.

Flaming Web (Recharge 5-6). Ranged Weapon Attack: +14 to hit, range 30/60 ft., one creature. Hit: The target is restrained by webbing. As an action, the restrained target can make a DC 20 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 20; hp 50; vulnerability to cold damage; immunity to bludgeoning, poison, and psychic damage), also at the start of a creatures turn they take 1d10 fire damage. 

The bebilith can take 2 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 bebilith regains spent legendary actions at the start of its turn.

Rendng claw (Costs 1 Actions). The bebilith makes 1 rending claw attack.

Flaming webs (Costs 2 Actions). The bebiliths flaming webs instantly recharges and uses it.