Multiattack. The ghostwalk spider makes one Bite attack and one Ghostly Snare attack, or it makes two Bite attacks.

Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 21 (3d10 + 5) piercing damage. If the ghostwalk spider is in its true form, the target must make a DC 15 Constitution saving throw, taking 13 (3d8) poison damage on a failed save, or half as much damage on a successful one. If the poison damage reduces the target to 0 hp, the target is stable but poisoned for 1 hour, even after regaining hp, and is paralyzed while poisoned in this way.

Ghostly Snare (Ghostwalk Form Only, Recharge 4-6). Ranged Weapon Attack: +9 to hit, range 30/60 ft., one target. Hit: The target is restrained by invisible webbing. While restrained in this way, the target is invisible. As an action, the restrained target can make a DC 15 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 12; hp 15; immunity to bludgeoning, poison, and psychic damage).