Phase Spider

Ethereal Sight. The spider can see into both the Material Plane and Ethereal Plane.

Spider Climb. The spider can climb even on difficult surfaces and upside down on ceilings.

Web Walker. The spider ignores movement restrictions imposed by webs.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 9 (2d6+2) piercing damage and the target makes a DC 11 Constitution saving throw taking 14 (4d6) poison damage on a failure or half damage on a success. If the poison damage reduces the target to 0 hit points the target is made stable but poisoned for 1 hour even if it regains hit points and it is paralyzed while poisoned in this way.

Ethereal Jaunt. The spider magically shifts from the Material Plane to the Ethereal Plane or vice versa.