Chain titan

Immutable Form.  The titan is immune to any spell or effect that would alter its form.

Conductive. Whenever the titan takes lightning or fire damage each creature caught on its barbs takes a max of 3d6 of the triggering damage roll.

Magic resistance.  The titan has advantage on saving throws against spells and other magical effects.

Magic Weapons.  The titan's weapon attacks are magical.

Seige monster.  The titan deals double damage to objects and structures.

Multiattack. The titan makes 3 Slam attacks

Slam. Melee Weapon Attack: +14 to hit, reach 15 ft., 1 target. Hit: 29 (4d10 + 8) bludgeoning damage. 

Barbed launcher. (recharge special) The titan fires barbed hooks attached to chains out in a 120ft cone. Up to 9 creatures within the area must make a dexterity save DC19 or take, 6d8 piercing damage and be caught on the barb. A creature can move while caught but can't move further than 120ft away from the golem. A creature or creature within 5ft can use an action on its turn to remove the barb. The caught creature takes 2d8 slashing damage when the barb is removed from it.

Reel in.  The titan draws all the chains it fired out from its Barbed launcher. Each barb is pulled 40ft toward the titan and any creatures caught on the barbs are pulled with them taking 2d6 slashing damage. If a barb did not hit a creature it crates difficult terrain starting from the max range of the Barbed launcher. If creatures are pulled adjacent to the titan they are grappled by the titan in an unoccupied space within 5ft of the titan. Once all the chains are Reeled in Barbed launcher recharges. If a barb hits a structure the titan has advantage on any strength checks to pull the structure down.