Cavern Spider

Nimble Escape. The spider can take the Disengage or Hide action as a bonus action on each of its turns.

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

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

Multiattack.  The spider chooses one of three options for its attack: 1) Bite, 2) Web, or 3) Pierce and Spit Poison

Bite.Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 15 (3d8 + 2) piercing damage, and the target must make a DC 15 Constitution saving throw, taking 9 (2d8) poison damage on a failed save, or half as much damage on a successful one. If the poison damage reduces the target to 0 hit points, the target is stable but poisoned for 1 hour, even after regaining hit points, and is paralyzed while poisoned in this way.

Pierce. Melee Weapon Attack: +5 to hit, range 15/30 ft., one creature.  Hit: 18 (3d10 + 2) piercing damage.

Spit poison. Ranged Weapon Attack: +6 to hit, range 30/60 ft. one creature.  The target must make a DC 15 Constitution saving throw, taking 9 (2d8) poison damage on a failed save, or half as much damage on a successful one. If the poison damage reduces the target to 0 hit points, the target is stable but poisoned for 1 hour, even after regaining hit points, and is paralyzed while poisoned in this way.

Web (Recharge 5–6).Ranged Weapon Attack: +6 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 13 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 10; hp 5; vulnerability to fire damage; immunity to bludgeoning, poison, and psychic damage).