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

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

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) piercing damage, and the target must make a DC 10 Constitution saving throw, taking 2 (1d4) 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.

Ethereal Skitter (Recharge 4–6). The spider can magically shift from the Material Plane to the Ethereal Plane until the start of its next turn.