Unknown Specimen 3, referred to as Spooper in the game files, is one of the new specimens encountered in Endless Mode.
Spooper's normal form resembles a child wearing a ghost costume and black sneakers. The sheet is white and featureless with two eyeholes. It will become tattered and soaked with blood the more it is struck with the Axe, and in its bloodiest form, an eye can be seen inside its chest cavity.
As the chase starts, Spooper's parasite form resembles a pink fleshy ball that floats through the air. A single eye is located in the center of its body and it has two arms that claw at the air while it chases the player.
Spooper will first be found standing in front of the exit door of any given room where he might spawn. He turns to face the player extremely slowly. The door cannot be entered when he is blocking it, forcing the player to use the axe on him.
Upon entering another room, Spooper will appear again blocking the exit, bloodied from the previous encounter. The player must continue to strike him with the axe and move to the next room, Spooper becoming more injured each time. After destroying him in his most injured and sixth state, entering the next room will begin his chase.
The grimy rooms the chase takes place in are filled with a caustic air that will drain the player's health slowly. During the chase, Spooper occasionally flashes in the room and the pink parasite form spawns, but doesn't do any harm. Sometimes, the player will fall to the ground and choke up blood, inhibiting movement and depleting a substantial amount of health.
Vomiting can be cancelled by going through a door at the same time as it occurring, which allows the player to negate damage.
When he kills you, a text will appear:
"Beyond that door is another world.
A world made of dreams...
A world where all your fantasies have come true.
A world full of everyone's sick fantasies.
A world lusting to include you."
"SPOOPER AMB", Unknown Specimen 3's chase theme
- Because the doors aren't disabled when Spooper appears, in some rooms it's possible to go around it and enter the next room. Thus, Spooper will appear in the state it was in during the last room and continue to do so until it's hit or the player enters a save point.
- Sometimes, when the player vomits, there is a chance that a fetus-like creature covered in blood will appear.
- According to the developers, upon hitting Spooper for the final time, the rooms get filled with spores. These spores then form a fetus within the Protagonist's stomach, impregnating them.
- It could also be a reference to an infamous scene in Silent Hill 3, in which the protagonist vomits up a monster that takes the form of a fetus.
- Unknown Specimen 3, along with Specimen 5, Unknown Specimen 1, and Monster 5 are the only specimens that can change the textures of the walls in normal rooms.
The parasite form will now appear more rarely and relatively smaller. Instead, Spooper's bloodied form will occasionally flash on the screen, slowly turning towards the player before disappearing.
Its chase music will now start as soon as Spooper first blocks the door instead of only after being "killed".
Spooper's original form will now teleport to the door the nearest to the player, preventing them from bypassing it in rooms with multiple doors.
Spooper's damage output has been significantly reduced, although it now disables healing, putting its new output comparable to its original version. Also, the player will be slowed down while vomiting instead of completely stopping movement. The player will not vomit if there is another specimen/monster around. Spooper will now stay in his normal form for 2 rooms instead of one. The wall textures will not change to the dirty texture until the player has gone 2 rooms after "killing" spooper, although their heath can still drain in the normal textured room