Homebrew, Monster Manual (5e)
Pack Tactics. The spider has advantage on an attack roll against a creature if at least one of the spider's allies is within 5' of the creature & the ally isn't incapacitated.
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.
Bite. Melee Weapon Attack: +5 to hit, reach 5', one creature. Hit: 7 (1d8 + 3) piercing damage, and the target must make a DC 11 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, & is paralyzed while poisoned in this way.
Web (Recharge 5–6). Ranged Weapon Attack: +5 to hit, range 30'/60', one creature. Hit: The target is restrained by webbing. As an action, the restrained target can make a DC 12 Strength check, bursting the webbing on a success. The webbing can also be attacked & destroyed (AC 10; hp 5; vulnerability to fire damage; immunity to bludgeoning, poison, & psychic damage).
Nimble Escape. The spider can take the Disengage or Hide action as a bonus action on each of its turns.
Any Climate; Subterranean; Forest, Hills, Swamps, Underdark, Urban