Chromatic Assault Golem

Absorption. At the beginning of its turn, the golem can choose to be not only immune to fire (red), cold (dark blue), radiant (white), lightning (yellow), or acid damage (green), but it also regains a number of hit points equal to the damage dealt from two of these types of damage. Its color changes for each damage type.

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

Magic Resistance. The golem has advantage on saving throws against spells and other magical effects.

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

Multiattack. The golem makes two attacks.

Arbalest Strike. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 20 (3d8 + 7) piercing damage. The creature must make a DC 18 Strength or Dexterity save to not be impaled upon the arbalest's loaded bolt, which would consider it grappled.

Quad-Prong Arm-balest. Ranged Weapon Attack: +6 to hit, range 150/600 ft., one target. Hit: 17 (2d8 + 8) piercing damage.

Head Cannon. Ranged Weapon Attack: +7 to hit, range 100/400 ft., one target. Hit: 33 (8d6 + 5) bludgeoning damage. If aimed at a point on the ground, creatures within a 5 foot radius must make a DC 13 Dexterity saving throw or take 4d6 bludgeoning damage, or half on a save. Creature is blinded after it has fired this weapon until its next turn.

Launch. The golem fires a bolt from its arbalest that is a impaled in a creature. The creature is launched half the effective range of the arbalest, then is impaled to the ground or targeted creature if fired at one and it hits. The creature can then either make a DC 15 Strength check to break the bolt and get off, or can make a DC 15 acrobatics check to pull itself off of the bolt.

Prepared Shot: If the golem is struck by an attack while not under the effects of its head cannon attack, it can use its reaction to prepare both arbalests and its cannon to fire on that target at the beginning of its next turn, instantly using its action, but giving each of those attacks a +3 to hit.

Shake Off the Powder. The golem shakes its head, and spent gunpowder falls from the end of the cannon, ending any blindess effect on it, including that caused by its head cannon attack.

Legendary Actions x3 per turn
Lock and Load: The golem reloads one of its weapons.

Uh oh. (costs 2 legendary actions): The golem makes a roaring sound from... somewhere. All creatures within 30 ft. must make a DC 15 Wisdom save or be frightened. A creature that succeeds this save is immune until the next time it receives a long rest.