Other than the common symptoms caused by sleep deprivation, some victims of SCP-966 have shown signs of suffering from extremely vivid hallucinations, as well as sudden bouts of rage with no apparent external stimuli. It is currently thought that these are the effects of prolonged exposure to the waves. Why SCP-966 continually exposes these waves to only some of their victims is unknown. One hypothesis is that SCP-966 will only do this when starving, since it further degenerates the physical and mental state of their prey, incapacitating it at a faster rate.
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SCP-966 instances can be found in their containment chamber and in the maintenance tunnels. They are only able to be seen when the player is wearing a pair of night vision goggles, although their sounds can still be heard when nearby regardless and the player is still able to collide with the instances. If the player approaches an instance without wearing the goggles, a message will be displayed, reading "You feel something breathing right next to you".
The instances will idly walk around the facility. Should the player approach an instance, it will look up at them and begin emitting a sound that will prevent the player from falling asleep. This is signified by the player's vision becoming blurred for a few seconds. Should the player remain close to an instance for a period of time after the sound is emitted, they will pursue and attack the player. The instances however are slow and easy to evade. Although they may prove difficult to avoid should the player not have night vision goggles.
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