Abomination (5A)

This is a Bogeyman subclass.

Powered by unnatural chemicals, the flesh of the abomination stands unyielding against the hail of arrows pelting her from the battlements as she charges forward, slamming into and through the barred gate to shatter it to pieces.

You are a creature of occult science or mystery, a construct made out of inanimate materials or even a terrifying homunculus of stitched together body parts, driven to monstrous form by forbidden alchemical secrets.

Source: En5ider 83.

Abominable Appearance

You have a monstrous appearance and need to conceal your appearance among humanoids. A simple cloak gives you a degree of anonymity. When interacting with humanoids, you suffer disadvantage on all Charisma checks except Intimidation checks.

Abominable Nature

Starting at 1st level, your creature type changes to construct. You gain immunity to disease, poison damage, and the poisoned condition. You do not need to breathe, eat, or drink, though you still require periods of rest similar to sleep.

Unnatural Threshold

Beginning at 3rd level, you gain immunity to the blinded, deafened, and exhaustion conditions.

Toughened Hide

At 6th level you gain resistance to bludgeoning, piercing, and slashing damage. Magical weapons ignore this resistance.

Rampage

At 7th level, you can easily destroy construction such as doors, chests, and walls, and unattended objects. You have advantage on attack rolls against and Strength (Athletics) checks to break or grapple such targets. Your Dark Strike deals double damage against such targets and ignore any damage threshold or damage resistance the target has.

Strange Resistance

Starting at 11th level, choose one type of damage that is not bludgeoning, force, piercing, poison, or slashing. You gain resistance to this type of damage.

Unstoppable

Beginning at 15th, you gain immunity to the paralyzed, petrified, and stunned conditions.

Invulnerable

When you reach 20th level, you gain resistance to all types of damage.