Nightmare is a deceiving, erratic, and unpredictable. He's Intelligent, and often comes up with countless schemes to bring absolute suffering to existence. He’s filled with hatred for everything, wanting everyone to be in a perpetual state of torment. He is 32ft tall and is waist up a skeleton, and he has octopus tentacles where his legs should be. His skeleton half is covered in a black goop (negativity). He is missing his left eye, and his right eye is pure teal, no pupil.