Vannagolem Mark 15

Anchored. Vannagolem Mark 15's main body has 0 speed and cannot be moved by any means.

Dismantled Form. Vannagolem Mark 15 can disconnect its fists, and use them in combat. These fists are physically separate from each other and the main body, and are used as weapons for the Vannagolem's attacks. They can still be targeted and damaged, although any damage is halved as they are disconnected from the main body. The fists cannot be farther than 90 ft away from the main body, and can move up to 30 ft on the Vannagolem's turn. When the Vannagolem makes an attack, it selects one fist, and attacks a creature within 5 ft.

Mantled Form. When the Vannagolem enters its mantled form, it loses any vulnerabilities, gains resistance to all damage, and becomes immune to any damage that it was resistant to. It also cannot make any actions or attacks. 

Legendary Resistance (2/Day). If Vannagolem Mark 15 fails a saving throw, it can choose to succeed instead.

Magic Resistance. Vannagolem Mark 15 has advantage on saving throws against spells.

Downward Smash. Area of Effect: 5 x 5 ft. space, all creatures within the targeted space must make a Dexterity saving throw (DC: 13) or take 2d8+7 bludgeoning + 5d6 force damage.

Restraining Grasp. Targetted Effect: One target. The target must make an acrobatics or athletics check against Vannagolem Mark 15’s athletics check (+12) or become restrained. At the beginning of each of the target’s next turns, they take 2d4 force damage. They may attempt to escape as an action on their turn.

Striking Blow. Melee Weapon Attack: +12 to hit, one target. Hit 2d6+7 bludgeoning + 2d4 force damage

Change Form. Vannagolem Mark 15 enters either its dismantled form or its mantled form, whichever it is not in currently.

Secondary Fist. Vannagolem Mark 15 makes a Striking Blow attack.

Vannagolem Mark 15 can take 1 legendary action, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Vannagolem Mark 15 regains spent legendary actions at the start of its turn.

Extra Action. Vannagolem Mark 15 takes an action.

Ping. All creatures within 90 feet of Vannagolem Mark 15 must make a stealth check (at disadvantage if within 5 feet of any part of Vannagolem Mark 15), and Vannagolem Mark 15 makes a perception check. If Vannagolem Mark 15 is able to detect any creature, that creature is pinged and cannot gain advantage or extra damage from flanking, sneak attacks, or any other ability that otherwise grants advantage from lack of sight until the end of the Vannagolem's next turn.