Piercer

Piercer Medium monstrosity, unaligned 1/2 100 xp

Armor class 15 (natural armor)
Hit points 22 (3d8 + 9)
Speed 5 ft., climb 5 ft.

STR 10 (0)
DEX 13 (+1)
CON 16 (+3)
INT 1 (-5)
WIS 7 (-2)
CHA 3 (-4)

Skills: Stealth +5

Senses: blindsight 30 ft., darkvision 60 ft., passive Perception 8

Languages: none

Challenge: 1/2 (100 xp)

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.

Actions

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.

Troglodyte

Troglodyte Medium humanoid, chaotic evil 1/4 50 xp

Armor class 11 (natural armor)
Hit points 13 (2d8 + 4)
Speed 30 ft.

STR 14 (+2)
DEX 10 (0)
CON 14 (+2)
INT 6 (-2)
WIS 10 (0)
CHA 6 (-2)

Skills: Stealth +2

Senses: darkvision 60 ft., passive Perception 10

Languages: Troglodyte

Challenge: 1/4 (50 xp)

Chameleon Skin. The troglodyte has advantage on Dexterity (Stealth) checks made to hide.

Stench. Any creature other than a troglodyte that starts its turn within 5 feet of the troglodyte must succeed on a DC 12 Constitution saving throw or be poisoned until the start of the creature's next turn. On a successful saving throw, the creature is immune to the stench of all troglodytes for 1 hour.

Sunlight Sensitivity. While in sunlight, the troglodyte has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

Actions

Multiattack. The troglodyte makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target.
Hit: 4 (1d4 + 2) piercing damage.

Claw. Melee Weapon Attack: +4 to hit, reach 5 ft., one target.
Hit: 4 (1d4 + 2) slashing damage.