Sentinel Sphere

Tiny construct, chaotic evil

Armor Class 16 (natural armor)
Hit points 7 (3d4)
Speed 0 ft., fly 60 ft. (hover)

STR	DEX	CON	INT	WIS	CHA
3 (-4)	19 (+4)	10 (+0)	1 (-5)	12 (+1)	6 (-2)

Damage Vulnerabilities thunder
Damage Immunities necrotic, poison
Condition Immunities deafened, blinded, petrified, poisoned
Skills Perception +3, Stealth +6
Senses tremorsense 60 ft. (blind beyond this radius), passive Perception 15
Languages –
Challenge 1 (200 XP)

Actions

• Drill. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 7 (1d6 + 4) piercing damage, and the sentinel sphere attaches to the target. If the target is Medium or smaller humanoid and the sentinel sphere has advantage on the attack roll, it attaches to the target’s head. While attached to the target, the sentinel sphere can attack no other creature except the target but has advantage on its attack rolls. The sentinel sphere’s speed also becomes 0, it can’t benefit from any bonus to its speed, and it moves with the target. A creature can detach the sentinel sphere by making a successful DC 14 Strength check as an action. On its turn, the sentinel sphere can detach itself from the target by using 5 feet of movement.

About

Sentinel spheres are the encased brains of victims captured by thin strangers. They are incredibly fast and highly maneuverable but are essentially pawns in the service of their commanding thin stranger. Thin strangers also use them to open dimensional gates, allowing them to hop planes at will.

Because the sentinel spheres require brains, they tend to take up residence in graveyards and funeral homes. But given the choice, thin strangers are not above taking brains from living people.