If you blink while it's near, or you don't keep it in direct line of sight, it'll kill you by snapping your neck, thus making you return to the main menu. SCP-173 could possibly be the first SCP that you'll encounter in-game. SCP-173 in a cage while being contained by the Mobile Task Force.
The enclosure must be cleaned on a bi-weekly basis. The reddish brown substance on the floor is a combination of feces and blood. This is considered normal, and any change in this behaviour should be reported to the acting HMCL supervisor on duty. Personnel report sounds of scraping stone originating from within the container when no one is present inside. In the event of an attack, personnel are to observe Class 4 hazardous object containment procedures. Object is reported to attack by snapping the neck at the base of the skull, or by strangulation.
Personnel assigned to enter container are instructed to alert one another before blinking. Line of sight must not be broken at any time with SCP-173. The object cannot move while within a direct line of sight. SCP-173 is animate and extremely hostile. It is constructed from concrete and rebar with traces of Krylon brand spray paint.