1. Darkvision: 120 ft. (due to its numerous eyes).
2. Undead Resilience: Immune to poison and exhaustion. Has advantage on saving throws against being charmed or frightened.
3. Wall Crawler: Can move along walls and ceilings without needing to make an ability check.
4. All-Seeing Eyes: Advantage on Wisdom (Perception) checks and saving throws against illusions.
5. Undead Regeneration (optional): Regains 10 hit points at the start of its turn unless it has taken radiant damage.

• Multiattack: The monster can make two tentacle attacks and one bite attack.
• Tentacle: Melee Weapon Attack: +7 to hit, reach 15 ft., one target. Hit: 10 (2d6 + 4) bludgeoning damage. The target must succeed on a DC 15 Strength saving throw or be grappled (escape DC 15).
• Bite: Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 15 (3d6 + 4) piercing damage. If the target is grappled, the bite deals an additional 5 (1d10) necrotic damage.

Shifting Structure: The Tentacled Undead Horror rearranges its form to become harder to hit. It takes the Dodge action until the start of its next turn, as its body rapidly shifts and twists unnaturally.

Unnatural Adaptation: Once Per Long Rest you can add +10 to a saving throw of your choice

• Eye Beam (2 actions): The monster fires a beam of necrotic energy from one of its eyes. Ranged Spell Attack: +6 to hit, range 60 ft., one target. Hit: 14 (4d6) necrotic damage. The target must succeed on a DC 15 Dexterity saving throw or take full damage (half damage on a success).
• Tentacle Storm (2 actions): The monster thrashes its tentacles wildly. Each creature within 10 feet must succeed on a DC 15 Dexterity saving throw or take 18 (4d8) bludgeoning damage and be knocked prone. Creatures that succeed on the save take half damage and are not knocked prone.

Mythic Action Name. Enter the description for how mythic actions work for your monster here.

Mythic Action Name (Costs # Actions). Enter the description for your mythic action.