Monster 6 appears as a tall, pale-skinned woman. She has a smile that almost stretches across her entire face, long black hair, and no eyes. She wears a black, floor-length gown with a dark red pattern on the front that resembles innards. Her hands are black and featureless except for her fingers, which are covered with blood.
Monster 6 is a secret monster encountered while going down the endless corridor in the basement. If the Protagonist walks down the corridor for a long period of time, she will slowly appear at the end. Once the player character is close enough to Monster 6, she will make a jumpscare and kill them, leaving the message:
"Don't get up before Saturday."
Monster 6 appears in the main game's Endless Mode, being one of the many creatures who can randomly engage the player character in a chase. During the chase, a dark, foggy overlay limits the player's vision. Monster 6 deals around 1/3 damage to the Protagonist, and does not pause in-between her attacks, leaving little room for error. This makes dead ends and head-on collisions with her very hazardous.
"BEKKA AMB", Bekka's chase theme.
- She is the only enemy that cannot be killed with the Sword.
- She is also the only enemy from the DLC and the 4th enemy in game that can kill the Protagonist in one hit.
- Her corridor will still appear when Monster 4 chases the player character.
- Monster 6's name, appearance, and death screen could be a reference to celebrity Rebecca Black and her infamous song, "Friday".
- She is functionally identical to Specimen 9's regular form, although the corridor does not close in on the Protagonist for her event.
- She is the only monster in the DLC that doesn't have a 3D model.