False Appearance. While the piercer remains motionless on the ceiling, it is indistinguishable from a normal stalactite.

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

Undead Fortitude. If damage reduces the zombie to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombie drops to 1 hit point instead.

Drop. Melee Weapon Attack: +3 to hit, one creature directly underneath the piercer. Hit: 3 (1d6) piercing damage per 10 feet fallen, up to 21 (6d6). Miss: The piercer takes half the normal falling damage for the distance fallen.