Phase Spider

The monster can see 60 feet into the Ethereal Plane when it is on the Material Plane.

The monster can climb difficult surfaces, including along ceilings, without needing to make an ability check.

The monster ignores movement restrictions caused by webs, and the monster knows the location of any other creature in contact with the same web.

The monster makes two attacks.

. . If this damage reduces the target to 0 Hit Points, the target becomes Stable, and it has the Poisoned condition for 1 hour. While Poisoned, the target also has the Paralyzed condition.

The monster teleports from the Material Plane to the Ethereal Plane or vice versa.