Physically, SCP-513 is an unremarkable, rusty cowbell. No marks or engravings are visible on its surface due to the large amount of corrosion. Attempts to remove the rust chemically or mechanically have had no success. SCP-513 was recovered by Agent ██████ while carrying out Containment Reestablishment Procedure Mu at Site-██. SCP-513’s clapper was firmly held in place by several strips of duct tape. A single scrap of paper was found along with SCP-513 (see Addendum). Any noise produced by SCP-513 immediately induces strong anxiety in all sentient beings who hear it, regardless of their previous mental status. Exposure victims report feelings of being watched by an unseen entity and present elevated heart rates and blood pressure. Roughly one hour after exposure, exposure victims begin to catch glimpses of SCP-513-1 when opening doors, walking past mirrors, turning their heads, or performing any other actions that result in a sudden change in visual perception. Upon being sighted, SCP-513-1 reportedly turns away and runs out of view before disappearing without a trace. Questioning of bystanders indicates that SCP-513-1 is invisible to those who have not been exposed to SCP-513. Sightings of SCP-513-1 reoccur every 14 to 237 minutes. This “stalking” behavior inevitably causes extreme sleep deprivation, as victims are frequently disturbed by SCP-513-1’s presence in their quarters. Victims able to fall asleep before SCP-513-1's appearance report being physically assaulted by it. Upon the victim's awakening, SCP-513-1 flees as usual (see Experiment Log 513). This sleep deprivation, along with the mental stress caused by SCP-513-1's behavior, invariably induces paranoia, aggression, hypervigilance, and depression. All test cases but one have ended with the test subject’s suicide.
- SCP-513 is a bell that can be rang using the right mouse button.
- The players that hear the sound of SCP-513 will be haunted by SCP-513-1.
- SCP-513-1 appears randomly near the player for a brief second.
- SCP-513-1 follows the player even after death.
- SCP-513-1 vaguely resembles a skeleton.