Cerberus Atlas Mech (Mass Effect 3)

Armor Plates. The Atlas has 5 armor plates (4 general plates and 1 chest plate) that shield it from harm. While all of these plates are intact, the Atlas has resistance to all damage. Each of the plates is considered to be worn/carried, and cannot be removed by any means other than direct damage. Each general plate is a small object with 25 AC and 50 hit points. Once one of these plates drops to 0 HP, it falls off the Atlas. The atlas suffers a -1 penalty to AC for every plate it has lost. The chest plate is a medium object with 25 AC and 100 hit points. Until the chest plate is destroyed, the cockpit cannot take damage. The Chest plate can be targeted under any circumstances, but cannot be knocked off unless 2 or more general plates have also been destroyed. If the chest plate would be reduced to 0 HP but the Atlas has 3 or more general plates remaining, the plate instead survives at 1 HP. Once the chest plate has been destroyed, the cockpit can begin taking damage.

Diagnostic AI. If the Atlas spends at least one minute interacting with a creature in combat, then the pilot becomes aware of the target's CR or Level (whichever is relevant), along with their damage adjustments (vulnerabilities, resistances, and immunities).

Glass Cockpit. If the Atlas takes damage from a critical hit, the damage does not impact the Atlas' HP and instead directly attacks the cockpit window. Any attack that hits the window automatically hits. The window has 75 HP. If the window is broken, then the pilot is vulnerable to all attacks. A character can hijack an empty atlas if the pilot is dead by making a dc18 raw wisdom check. A creature inside the cockpit must take the pilot action on its turn to control the Atlas. If it does, the creature forfeits the rest of its turn and the Atlas takes its turn immediately after the pilot, acting under the pilot’s control. If the pilot leaves or dies, the Atlas becomes inert. While the glass is broken, the pilot has +5 bonus to AC, in addition to any other bonuses.

Shields. The Atlas can have up to 100 temp HP at once from this ability. At the start of each of the atlas' turn, if its temp HP reserve is below 100, it must make a constitution saving throw (DC=10 +1 for every 10 temp HP below 100), healing 2d4+7 damage on a successful save and half as much on a failed one. If the Atlas' temp HP reserve is reduced to 0, it stops generating temp HP.

Siege Tank. The Atlas has disadvantage on all dexterity saving throws, and advantage on all strength saving throws.  

Systems Failure. If the Atlas is reduced to 0 hp, it explodes, causing damage in a 10 foot sphere centered around itself. Any creature within that radius must make a dc16 dexterity saving throw or take 10d4 fire damage.

Targeting AI: The Atlas has advantage on all melee and ranged weapon attacks made against stationary targets.

Multiattack. The Atlas makes 3 attacks.

Ground Slam. The Atlas raises both arms and slams them down in a 10 foot square directly in front of itself. All creatures within that area must make a dc20 dexterity saving throw, falling prone and taking 6d8 bludgeoning damage on a failed save. On a success, the target takes half as much damage but is still knocked prone.

Brutal Swipe. The Atlas swings its arm out in a 10 foot semicircle.  All creatures within that area must make a dc20 dexterity saving throw, taking 4d10 bludgeoning damage and being pushed back 10 feet on a failed save. On a success, the target takes half as much damage and is instead knocked back 5 feet.

Light Anti-Personnel Cannon. The Atlas fires four cannon shots in a direct line between 20-80 ft. from itself, causing damage in a 2.5-foot sphere from where each projectile lands. any creature or object in the area must make a dc18 dexterity saving throw, taking 2d6 fire damage on a failed save and half as much on a successful one. A creature can take damage from multiple projectiles at once.

Targeted Missile. The Atlas Launches chooses a target within 100 feet of it that it can see. It then launches an AI-controlled missile at the target. The missile has a speed of 60 feet and cannot turn around sharp corners. When the missile strikes a creature or object, it explodes in a 5-foot sphere centered around the strike point. Every creature within that area must make a dc17 dexterity saving throw, taking 5d6 fire damage on a failed save and half as much damage on a successful one. The creature or object that was struck automatically  fails this saving throw.

Crush. If the Atlas makes a brutal swipe attack and there is a creature within 10 feet of it immediately afterward, the Atlas can grab the player with its clawed hand. The creature must succeed on a dc17 dexterity saving throw or become restrained by the Atlas. While restrained in this way, the target cannot make attacks and cannot take reactions or bonus actions. If the Atlas has a creature restrained in this way, it can use its bonus action in an attempt to crush the target. If it does, the target must succeed on a dc16 constitution saving throw or take 8d12 force damage as the Atlas crushes it. Once the Atlas has taken this bonus action, it immediately releases the creature and cannot target that creature again for 1d4 rounds. The Atlas can only have 1 creature restrained in this way at any time.