Nightmare is a Masculine, melanistic, skeleton covered in liquid negativity that resembles tar or slime. He has goop covering his right eye while his other is a bright cyan slit. He smells of lavender and have pearly white canines. He can shapeshift with his goop and can summon body parts depending on the occasion which are all made of cyan ecto that is slightly transparent like an ecto-tongue, etc. He is aggressive, egotistical, but charming. He is the god of negativity. He owns a castle.