Phantom Webs. Ghostwalk spiders spin ephemeral webs in secluded areas. They spend most of their time stalking prey to paralyze and drag back to their phantom web. As long as these remains lie tangled in ghostly webs they go unnoticed by material creatures, but the spiders eventually cast old kills aside. Adventurers are wise to fear empty caves containing unexplained, desiccated remains.
Multiattack. The ghostwalk spider makes two bite attacks. It can make a ghostly snare attack in place of one of its bites. Bite. Melee Weapon Attack: 1d20+9 to hit, reach 5 ft., one target. Hit: 16 2d10+5 piercing damage plus 13 3d8 poison damage, or half poison damage with a successful DC 15 Constitution saving throw. If the poison damage reduces the target to 0 hit points, the target is stable but poisoned and paralyzed for 1 hour, even after regaining hit points. While using Ghostwalk, the spider’s bite and poison do half damage to targets that aren’t affected by Ghostly Snare (see below). Ghostly Snare (During Ghostwalk Only, Recharge 5-6). Ranged Weapon Attack: 1d20+9 to hit, range 40/160 ft., one target. Hit: The target is Restrained by ghostly webbing. While restrained in this way, the target is Invisible to all creatures except ghostwalk spiders, and it has resistance to acid, cold, fire, lightning, and thunder damage. A creature restrained by Ghostly Snare can escape by using an action to make a successful DC 14 Strength check, or the webs can be attacked and destroyed (AC 10; hp 5).
Ghostwalk. As a bonus action, the ghostwalk spider becomes Invisible and intangible. Attacking doesn’t end this invisibility. While invisible, the ghostwalk spider has advantage on Dexterity (Stealth) checks and gains the following: Damage Resistances acid, cold, fire, lightning, thunder; bludgeoning, piercing, and slashing damage from nonmagical weapons Condition Immunities paralyzed, petrified, prone, restrained, stunned The ghostwalk ends when the spider chooses to end it as a bonus action or when the spider dies.
A pasty-white spider the size of a horse slinks through the shadows. Its dull eyes fix on you as it fades from sight with a ghostly blue shimmer. Ghostwalk spiders are malevolent hunters that sprang from misguided experiments on phase spiders. They are spindly, emaciated things all but devoid of color. The spider is 8 feet in diameter (including legs) and weighs 500 pounds.