Medium Undead, chaotic evil
Armor Class 15 (natural armor)
Hit Points 112 (15d8+45)
Speed walk +30, climb +30
Challenge 7
Saving Throws con +6
Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities necrotic, poison
Condition Immunities charmed, exhaustion, poisoned
Senses darkvision 60 ft., passive Perception 10
Languages Common
Spider Climb. The dissimortuum can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Multiattack. The dissimortuum makes three claw attacks.
Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 15 (3d8 + 2) slashing damage.
Terrifying Mask. Each non-undead creature within 60 feet of the dissimortuum that can see it must make a successful DC 15 Wisdom saving throw or be frightened for 1d8 rounds. If a target's saving throw is successful or the effect ends for it, the target becomes immune to all dissimortuum's terrifying masks for the next 24 hours.
Source: Tome of Beasts · OGL/Open