Crystal Spider

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.

Crystal Sense: While in contact with a crystal, the spider know the relative location on any other creature that has hit a crystal within one turn.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., 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, and is paralyzed while poisoned in this way.

Web (Recharge 5–6). Ranged Weapon Attack: +5 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 12 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).

Impale (bonus action): The Crystal Spider stabs several of its feet at a point on the ground within 15 feet of it. Any creature in a 5-foot-radius, 10-foot-high cylinder centered on this point must succeed on a DC 12 Dexterity saving throw or take  (1d6+3) piercing damage and fall prone. Until the uppskeru uses its Impale again or moves, the creature is restrained. While restrained in this way, the creature (or another creature within 5 feet of it can use its action to make a DC 11 Strength check. On a success, the creature relocates to an unoccupied space of its choice within 5 feet of the Crystal Spider and is no longer restrained.