This item about an "expressionless" apparition in a blood-covered gown who supposedly appeared at Cedars-Sinai hospital in 1972 isn't an historical account of an event witnessed by others and passed down over the span of forty years. It's merely a bit of supernatural fiction that gained widespread currency on the Internet after appearing on Creepypasta (a site for "short stories designed to unnerve and shock the reader") in June 2012.
In June of 1972, a woman appeared in Cedar Senai [sic] hospital in nothing but a white, blood-covered gown. Now this, in itself, should not be too surprising as people often have accidents nearby and come to the nearest hospital for medical attention, but there were two things that caused people who saw her to vomit and flee in terror.
The first being that she wasn't exactly human. she resembled something close to a mannequin, but had the dexterity and fluidity of a normal human being. Her face, was as flawless as a mannequins, devoid of eyebrows and smeared in make-up.
There was a kitten clamped in her jaws so unnaturally tight that no teeth could be seen, and the blood was still squirting out over her gown and onto the floor. She then pulled it out of her mouth, tossed it aside and collapsed.
From the moment she stepped through the entrance to when she was taken to a hospital room and cleaned up before being prepped for sedation, she was completely calm, expressionless and motionless. The doctors thought it best to restrain her until the authorities could arrive and she did not protest. They were unable to get any kind of response from her and most staff members felt too uncomfortable to look directly at her for more than a few seconds.
But the second the staff tried to sedate her, she fought back with extreme force. Two members of staff had to hold her down as her body rose up on the bed with that same, blank expression.
She turned her emotionless eyes towards the male doctor and did something unusual. She smiled.
As she did, the female doctor screamed and let go out of shock. In the woman's mouth were not human teeth, but long, sharp spikes. Too long for her mouth to close fully without causing any damage ...
The male doctor stared back at her for a moment before asking "What in the hell are you?"
She cracked her neck down to her shoulder to observe him, still smiling.
There was a long pause, the security had been alerted and could be heard coming down the hallway.
As he heard them approach, she darted forward, sinking her teeth into the front of his throat, ripping out his jugular and letting him fall to the floor, gasping for air as he choked on his own blood.
She stood up and leaned over him, her face coming dangerously close to his as the life faded from his eyes.
She leaned closer and whispered in his ear.
The doctor's eyes filled with fear as he watched her calmly walk away to greet the security men. His last ever sight would be watching her feast on them one by one.
The female doctor who survived the incident named her "The Expressionless".
There was never a sighting of her again.