It approaches by crawling or staggering. Upon contact, it begins to devour you; staying still leads to death. It can be killed through incorrect treatment methods or by force using a gun, taser, or fists.

It hides under the beds in the patient rooms. If you get close, it pulls you in; staying still leads to death. However, if you feed it a Hider, organs, or maple syrup, it will eat and disappear.

Attached to the ceiling. Looking at the eyes on the ceiling drains your health. Staying still while looking at them will eventually kill you. The way to deal with it is simply not to look.

It uses camouflage to hide on walls and such, then makes a strange noise and chases anyone who comes near. You can avoid it or kill it with a fire extinguisher, taser, or gun. You can gain an advantage by leading a Hider to a Bed Monster to eliminate both at once.

It continuously bangs its head against the glass of the patient check-in counter to break it. Telling it to leave drains your health, but you can send it away safely by giving it coffee.

It hides in corners. If a person sees the Stalker, it drains their health and quickly vanishes. Its true identity is unknown.

It suddenly appears while you are checking the security cameras. Looking at that specific camera drains your health before it disappears. It is terrifying.

Appears during slime events and devours people. It has a green slime appearance. Being eaten drains your health. It can be eliminated with cough syrup and fire extinguishers.

It suddenly bursts out when a patient in Operating Room 8 complains of stomach pain. It emerges from above, and being pulled up drains your health. It can be dealt with using surgical tools, but must be eliminated within 45 seconds.

Appears when a patient dies. If possessed by the ghost, your health drains every second until it leaves your body. Being a ghost, it is initially invisible. However, it can be eliminated with a taser, gun, or scanner.