Large Undead, chaotic evil
Armor Class 14
Hit Points 90 (12d10+24)
Speed walk +40
Challenge 4
Skills stealth +6
Damage Vulnerabilities radiant
Damage Resistances acid, cold, fire, lightning, thunder; bludgeoning, piercing and slashing from nonmagical weapons
Damage Immunities necrotic, poison
Condition Immunities exhaustion, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained
Senses darkvision 120 ft., passive Perception 11
Languages the languages it knew in life
Amorphous. The overshadow can move through a space as narrow as 1 inch wide without squeezing.
Shadow Stealth. While in dim light or darkness, the overshadow can take the Hide action as a bonus action.
Sunlight Weakness. While in sunlight, the overshadow has disadvantage on attack rolls, ability checks, and saving throws.
Multiattack. The overshadow makes two strength drain attacks.
Strength Drain. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 13 (2d8 + 4) necrotic damage, and the target's Strength score is reduced by 1d4. The target dies if this reduces its Strength to 0. Otherwise, the reduction lasts until the target finishes a short or long rest.
Bringer of Darkness. The overshadow dims the light around it. The radius of each light source within 60 feet of it is halved for 1 minute. The overshadow can't use this action while in sunlight.
Source: Tome of Beasts 2 · OGL/Open