Cable Leviathan

Anchored Core. The Leviathan is fused into the terrain by massive cable‑roots. It cannot move or be forcibly relocated.

Tentacle Network. The Leviathan can make melee attacks from any point within its reach. It ignores Quarter-cover when attacking.

Magnetic Field. Ranged weapon attacks against the Leviathan have disadvantage within 40 feet.

Overload Weakness. When struck by lightning damage, its tentacles seize. Until the end of its next turn, attack rolls against it have advantage.

Multiattack. The Leviathan makes four melee attacks, each targeting a different creature within reach.

Cable Tentacle. Melee Weapon Attack: +11 to hit, reach 25 ft., one target. Hit: 20 (3d8 + 6) bludgeoning damage, and the target must succeed on a DC 18 Strength saving throw or be grappled (escape DC 18). Grappled creatures are restrained.

Piercing Tendril. Melee Weapon Attack: +11 to hit, reach 25 ft., one target. Hit: 17 (3d6 + 6) piercing damage.

Crushing Coil. Melee Weapon Attack: +11 to hit, reach 25 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage. If the target is grappled by the Leviathan, it takes an additional 10 (3d6) bludgeoning damage.

The Cable Leviathan can take 3 legendary actions, choosing from the options below.

Magnetized Pull (Costs 2 Actions).

All creatures of its choice within 80 feet must make a DC 18 Strength saving throw or be pulled 40 feet directly toward it. Creatures that fail are knocked prone if they reach its base.

Armor Re‑Thread (Costs 3 Actions).

The Leviathan reconfigures its cables, ending one condition affecting it and regaining 20 hit points.