From SCP: Secret Laboratory Public Beta Official Wiki

Reinforced Concrete (Passive)

Heavy Armor level bullet resistance.
Higher penetration weapons are more effective.
Tantrum (Active)

A pool of filth on the ground that slows targets. Regain a small amount of HS when stained targets are killed.
Blink (Active)

Teleport to a marker on the ground, forcing everyone to blink. Will kill the nearest human if they are in range.
Break Neck Speeds (Active)

SCP-173 moves a lot faster and can blink further, but is unable to kill.
Health: 4000 Walk: 7.3 m/s
Hume Shield (Initial): 750 Break Neck: 12.4 m/s
Hume Shield (20% HP): 1500 Jump Power: 5
Hume Shield Regen: 20 HS/s
Hume Shield Regen Delay: 10s
Other Information
Spawn Location: Light Containment Zone
Nickname: Matthew
Class ID: 0
Class Color: #EC2222
Article Link: Page

SCP-173 is one of the seven playable SCP classes in SCP: Secret Laboratory.
SCP-173 acts as an assassin class SCP, meant to quickly hunt down and eliminate a single target or small groups of players.

Operational Guides

Class Operational Guide

A mere concrete sculpture upon first glance; an art piece to be seen and admired. 

On second glance, you’ll notice it’s somehow closer, as if yearning for attention.

There is no third glance. You’re dead by then.

“SCP-173 wasn’t the most peculiar anomaly in our containment. A sculpture capable of moving at high speeds when unseen. It attacks by breaking its victim’s neck. After its ‘mutation’, for lack of a better term, research and testing have resumed. Did the mutation make it our most peculiar anomaly? No, I doubt it did.”
-Dr. Simon Wolffe, SCP-173 Research Supervisor, Site-02

Abilities Operational Guides

- [M1] — Snap

While unobserved, press the Attack button to perform Snap on a human, killing them immediately. 

SCP-173 has been seen attacking subjects from behind. It attacks by snapping the neck at the base of the skull. The attack is carried out at a high speed, resulting in a severe and unnatural rotation of the spine; this is a minimum of 180 degrees.

- [M2] — Blink

Trigger Blink to catch your observers by surprise and rapidly attack the closest player. Press and hold Blink to have a marker of SCP-173 appear where you are facing. After releasing Blink, SCP-173 will rapidly move towards the marker’s last location, killing the nearest human in range. 

SCP-173 has been observed to attack subjects as far as 15 meters away in the span of a second.

- [Shift] — Breakneck Speeds

Activate Breakneck Speeds to greatly increase your movement speed; however, for as long as it is active, you will not be able to attack (though Tantrum may still be used). If a human observes you while Breakneck Speeds is active, you will lose your speed bonus rapidly. Alternatively, you can cancel Breakneck Speeds at any time by pressing the shift key.

After being transferred to Site-02, SCP-173 seems to have gained a new behavior. When unobserved, SCP-173 has been heard scraping and moving much faster than usual… …Interestingly, this has shown to negate its lethality.

- [F] — Tantrum

Activate Tantrum and cause SCP-173 to excrete a pool of filth on the ground. Humans caught in the pool will be unable to sprint, and gain the Stained status effect, which lasts for a short duration after the player leaves the pool. If SCP-173 kills someone while the player is under the effect, SCP-173 will instantly gain back a portion of its Hume Shield.

SCP-173 can only create a limited number of pools at a time. Creating more will result in the oldest dissipating.

SCP-173 has been known to cover its containment chamber in a caustic, sticky substance made of several distinct bodily fluids and [REDACTED]. The material has an orange, reddish colouration. Bubbles can be seen on the surface due to the presence of bodily fluids.

In Game

At the start of a round, SCP-173 will spawn in its Containment Cell in Light Containment Zone.
Upon spawning, SCP-173 won't be able to exit the cell right away, as the only exit (a gate) is locked shut, which gives the Class-Ds and Scientists some time to explore. After a short amount of time, the gate will automatically open, and SCP-173 can leave its cell, free to roam around the map. If SCP-173 takes no damage for 10 seconds, its Hume Shield will slowly regenerate by 20 HS/s. SCP-173 can talk to the other SCPs by holding down the Q key. This voice chat can be heard by all SCPs no matter the distance.

Hume Shield

  • SCP-173 has base Hume Shield value of 750.
  • If SCP-173 takes no damage for 10 seconds, its Hume Shield will slowly regenerate by 30 HS/s.
  • SCP-173 restores 400 Hume Shield if they kill a player under the Tantrum Effect.
  • Hume Shield does not factor in SCP-173's damage resistance.


Neck Snap

When SCP-173 isn't being observed, they can press  Left Click to snap a player's neck, instantly killing them. This attack will play a fairly audible sound effect, that can alert other players.

Reinforced Concrete

SCP-173 takes reduced damage from all firearms besides the Micro H.I.D. and the 3-X Particle Disruptor. This only applies to SCP-173's base HP and not their Hume Shield. This passive armor has a value of 80%, and will factor in a weapons penetration. Meaning it works the same as the Armor item. x = a(100% − p), where a is the armor protection level, p is the penetration amount of a weapon, with x being the actual damage reduced. So a weapon with 50% penetration shooting a player in the body would only reduce the damage by 40% instead of 80%.


SCP-173 can leave a pool of filth on the ground by pressing the F key. While multiple pools can be placed at once, the ability has a 30 second cooldown. A pool of filth will last only 180 seconds on the ground, though Tesla Gates will instantly destroy them, preventing SCP-173 from placing them near the Tesla Gate.
Players entering the pool gain the Stained Reduces player speed by 20%
Players cannot sprint
Status Effect, which lasts until the player leaves the pool plus three seconds afterwards. If SCP-173 kills a player while they are under the Stained Effect, they will instantly gain back 400 Hume Shield.


When SCP-173 is being looked at by a Human, SCP-173 will stop moving and be locked in place. A small HUD element will appear on SCP-173's screen displaying a 3.0 second countdown for their Blink ability. When the cooldown ends, the player can hold  Right Click make a marker appear on the ground. The marker can be moved by using the mouse and can travel up to a max distance of 8 meters. When the player releases  Right Click, SCP-173 will teleport to their mark, which will force humans to blink. If any humans are in range, SCP-173 will automatically kill the closest one. The marker will change colors to display if SCP-173 is within killing range of a human or if Breakneck Speeds is activated.
The Blink ability will shatter nearby windows when used.

Breakneck Speeds

Breakneck Speeds can be turned on by pressing Shift, and can be used whether or not SCP-173 is seen.
In this state, SCP-173 moves 1.7x faster, blinks 1.8x further, charges blinks twice as quickly, but is unable to kill players. The ability can be used by SCP-173 to quickly escape a dangerous situation as it allows them to move much more quickly at the cost of being unable to kill.
This mode ends when the player presses Shift again. There is a small grace peroid of 1.5 seconds after the ability is activated where pressing the Shift key will not cancel the ability. It will also ends automatically 10 seconds after SCP-173 is spotted.
The ability has a 40 second cooldown, the cooldown only starts after the ability ends.

Related Achievements

Click to view 1 achievement(s) related to SCP-173:

Don't Blink
Survive an encounter with SCP-173.


Sight Stingers
Chase Ambient
Attack Sounds
Ability SFX



  • SCP-173 doesn't have a ragdoll upon death, and instead falls apart into pieces when killed.
    • The Xmas 2021/2022 models would explode into a snowy mist and leave behind a black scarf and tophat.
  • Dying to SCP-173 will cause the player's head to be twisted 180 degrees around the base of the neck
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