Shapechanger. The werespider can use its action to polymorph into a spider-humanoid hybrid or into a spider, or back into its true form, which is humanoid. Its statistics, other than its AC, are the same in each form. Any equipment it is wearing or carrying isn’t transformed. It reverts to its true form if it dies.

Fey Ancestry. The Werespider has advantage on saving throws against being charmed, and magic can't put the Werespider to sleep.

Innate Spellcasting. The Werespider's innate spellcasting ability is Wisdom (spell save DC 13). The Werespider can only cast these spells in huminoid or hybrid form and can innately cast the following spells, requiring no material components:

At will: dancing lights

1/day each: darkness, faerie fire

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

Sunlight Sensitivity. While in sunlight, the Werespider has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

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

Sight of the Multi-Eyed. The werespider has advantage on Wisdom (Perception) checks that rely on sight.

Multiattack (Humanoid or Hybrid Form Only). In humanoid form, the werespider makes two scimitar attacks or two longbow attacks. In hybrid form, it can attack like a humanoid or make one scimitar attack and one bite attack or one weapon attack and one web attack (or vice versa)

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 2 (1d4) piercing damage plus 9 (2d8) poison damage.  If the target is a humanoid, it must succeed on a DC 13 Constitution saving throw or be cursed with Werespider lycanthropy.

Scimitar (Humanoid or Hybrid Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) slashing damage.

Longbow. Ranged Weapon Attack: +4 to hit, range 150/600 ft., one target. Hit: 7 (1d8 + 3) piercing damage plus 4 (1d8) poison damage.

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).

Sting (Spider or Hybrid Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 2 piercing damage. If the target is a humanoid, it must succeed on a DC 13 Constitution saving throw or  be poisoned taking 18 (4d8) 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.