Ancient Colossus

Pilot Bond. The Colossus can be piloted. A creature touching the Colossuses head can  bond with the Colossus, provided the Colossus is not already bonded to a creature. This process requires the creature to use their action, bonus action, and reaction to bond with the Colossus every round for 10 minutes. Their progress is reset if they take any damage. If a spelljamming helm is linked to the Colossus, a creature bonded to the Colossus and inside its head can use the spelljamming helm to take complete control of the Colossus. The creature may use an action to relinquish control of the Colossus, at which point they are lowered safely to the ground by the Colossuses entry lift. A creature bound to the Colossus who is within 10ft of the Colossuses foot can use an action to activate the entry lift, transporting themselves and any other creature within 10ft of the Colossuses foot to the inside of its head, arriving at the start of the bonded creature's turn 3 rounds later. A bonded creature can use an action to sever their bond with the Colossus. The bond is also severed if the bonded creature dies or if the Colossus is destroyed. If either the bonded creature or the Colossus takes 75 or more damage from a single attack, the bonded creature must make a DC 20 intelligence saving throw or have their bond with the Colossus severed. If the Colossus is not piloted, it is incapacitated and cannot move. The Colossus shares initiative count with its bonded creature. Whilst piloted, the Colossuses Intelligence, Wisdom, and Charisma scores become those of its pilot.

Ancient Artifice. The Colossuses weapon attacks and damaging abilities count as magical for the purposes of overcoming resistances and immunities.

Arcane Resonance. The Colossuses pilot can use their action (NOT the Colosusses) to send an amplified message using the Colossuses speakers. They speak a message aloud, which is then amplified in volume to be able to be heard from up to a mile away. Each creature within 15ft of the Colossus must succeed on a DC22 Constitution saving throw or take 10 (3d6) thunder damage.

A monster of many phases. When the Colossus would be reduced to 0 hit points or killed, it instead transforms into a Dreadnought Colossus at full HP. It is cleared of all conditions and regains all ability uses, reloading or recharging all weapons.

Multiattack. The Colossus makes two Crushing Fist attacks and uses Flamethrower if available. Alternatively, it makes 6 Kinetic Minigun attacks.

Crushing Fist. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 37 (5d8 + 15) bludgeoning damage.

Kinetic Minigun. Ranged Weapon Attack: +14 to hit, range 120/240 ft., one target. Hit: 9.5 (1d8 + 5) piercing damage. This weapon has 18 pieces of ammunition. After all ammunition is used, this weapon gains 3 Reload Points and cannot be used again until all Reload Points are removed from it. This weapon cannot target anything within 15ft of the Colossus.

Power Slam. Each creature within 15 ft of the Colossus must make a DC 22 Dexterity saving throw. On a failure, they take 51 (8d8+15) bludgeoning damage and are stunned until the start of the Colossuses next turn. On a successful save, they take half as much damage and are not stunned.

Rocket Mortar. The Colossus launches a barrage of self-propelled explosives towards a point on the ground between 60ft and 1200ft away from itself. The explosives land at the start of the Colossuses turn next round. When it lands, each creature within a 30ft radius sphere centred on that point must make a DC 22 Dexterity saving throw, taking 105 (10d10+50) bludgeoning damage and 105 (10d10+50) fire damage on a failed save, or half as much damage on a successful save. After firing this weapon, it gains 15 Reload Points and cannot be used again until all reload points are removed from it.

Flamethrower (Recharge 5-6). The Colossus fires a magical flamethrower, incinerating all nearby creatures. Choose up to ten 5ft x 5ft x 5ft cubes. Each cube must share at least one face with another cube. Each creature within that area must make a DC 22 Dexterity saving throw, taking 52 (15d6) fire damage on a failed save or half as much damage on a successful one.

Fortify. The Colossus deploys a magical barricade of force. The barricade is made of ten 10ft square panels that must all be connected to each other by at least one edge. They must be connected, directly or through another panel, to a solid surface. Once in place, the barricade functions like a Wall of Force, except that it only blocks physical objects. Spell effects and incorporeal creatures and objects can still pass through the barricade, and it does not extend into the ethereal plane. The barricade dissapears at the end of the Colossuses turn after one minute, or when the Colossus creates another barricade, whichever comes first.

Brace. The Colossus raises its shields, assuming a defensive posture. Until the start of its next turn, the Colossuses AC increases by 3, and any instance of incoming damage is reduced by 20. This cannot reduce damage below zero. This bonus action cannot be used if the Colossus has moved since the start of its last turn, and the Colossus cannot move or be moved whilst benefiting from this bonus action.

Reload. The Colossus removes two Reload Points from its weapons. It chooses how it distributes this reduction.

Magic Reflection. When the Colossus is dealt damage by a spell, it may use its reaction and roll a d8. On a 1-4, the spell takes effect as normal. On a 5-8, the spell does not affect the Colossus, and any damage the Colossus would have taken is instead stored by the Colossus. This damage cannot be used for now, but keep track of it for the Colossuses final phase (Avatar of Vengance).

The Colossus can take three legendary actions, only one at a time and only at the end of another creature's turn.

Pound. The Colossus makes a Crushing Fist attack.

Repulsion Shield. The Colossues AC increases by one until the start of its next turn, and any creature that hits the Colossus with a melee attack during this time takes 2d8 force damage and is pushed 15ft directly away from the Colossus. This does not stack.