Amphibious. Hekaton can breathe air and water.

Innate Spellcasting. The giant's innate spellcasting ability is Charisma (spell save DC 17). It can innately cast the following spells, requiring no material components:

At will: detect magic, feather fall, levitate, light

3/day each: control weather, water breathing

Multiattack. Hekaton makes two broken chain attacks.

Broken Chain. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit:18 (3d6 + 9) bludgeoning damage.

Ballista. Ranged Weapon Attack: +6 to hit, range 120/480 ft., one target. Hit:18 (3d10 + 2) piercing damage.

Lightning Strike (Recharge 5–6). Hekaton hurls a magical lightning bolt at a point he can see within 500 feet of it. Each creature within 10 feet of that point must make a DC 17 Dexterity saving throw, taking 54 (12d8) lightning damage on a failed save, or half as much damage on a successful one.

Thunderous Stomp (Recharge). Hekaton stomps the ground, triggering a thunderclap. All other creatures within 15 feet of him must succeed on a DC 17 Constitution saving throw or take 33 (6d10) thunder damage and be deafened until the start of Hekaton's next turn. On a successful save, a creature takes half as much damage and isn't deafened. The thunderclap can be heard out to a range of 1,200 feet.