APD (Autonomous Planetary Destroyer)

Magic Resistence. The destroyer has advantage on saving throws against spells and other magical effects.

Calculated Premonition. The destroyer changes to a different Multiattack every 1d8+1 turns. 

Advanced Scanner Array. The destroyer gains 300 ft. of truesight in all directions, and advantage on Perception Checks that use sight.

Siege Monster. The destroyer deals double damage to objects and structures.

Aura of Static. Upon going within 30 ft. of the destroyer, make a DC 19 Constitution Save. On a failed save, take (10d8) lightning damage, and be paralyzed

Magic Weapons. The destroyers weapon attacks are magical.

Multiattack Ω. The destroyer makes 1 attack with its Cannons, and 5 with its Rifles.

Ballistic Supercannons. Ranged Weapon Attack: +14 to hit, reach 300 ft., 1 target. Hit: 78 (10d10 + 14) fire damage. 

Heavy Artillery Rifles. Ranged Weapon Attack: +18 to hit, range 1000 ft., 1 target. Hit: 25 (3d6 + 14) piercing damage.

Multiattack β. The destroyer makes 2 attacks with its Seismic Generator

Seismic Generator 5000. The destroyer activates the seismic generator inside of its core. All creatures within a 600 ft. radius must make a DC 16 Dexterity save. On a failed save, the creature takes 30 (8d8) thunder damage, and is knocked prone.

Multiattack γ. The destroyer makes 2 attacks with its Laser Array, and 1 Shielding Action if possible.

Laser Array. Ranged Spell Attack: +18 to hit, range 300 ft., 1 target. Hit: 52 (12d4+14) force damage.

Auxiliary Shield Bubble Generator. The destroyer activates its auxiliary generator. Roll a d10x10. The destroyer gains temporary hit points equal to that number. You will be able to use this action again within 1d6+1 turns.

Scramble Missiles. (Costs 1 Action). The destroyer fires 2d8+2 homing missiles. The missiles lock on to a random target, and deal 1d6 fire damage on impact

Targeting Scan. (Costs 2 Actions). The destroyer scans a 300 ft. cone for any threat that it can find. Any creature must make a DC 18 Stealth Check. On a fail, the destroyer gains advantage on the next attack against the creature.

Protocol-500. (Costs 1 Action). The destroyer activates this when at 1/8 max health. The destroyer gains 1d6x10 temporary hit points, and will detonate in 2d20+20 turns. If the protocol succeeds, detonating the destroyer, dealing 560 (100d10) fire damage. If this attack drops a creatures hit points to 0, they are disintegrated. However, you can stop this process by destroying the temporary hit points, and dealing lightning damage equal to the destroyers spell save DC (26) If the process fails, the destroyer may do this action again in 40 (3d20+3) turns