Per 
SCP-XXXX "Too Light, Too Dark"
Object Class: Euclid
Containment Procedure:
SCP-XXXX must be kept in a cell with no windows which has a light source of approximately 850 lumens this bulb must be replaced at least once a month. If anyone is required to enter the cell SCP-XXXX must be moved to an identical room neighbouring his current containment, once the door in the first containment room has been shut SCP-XXXX is free to reenter the first containment area. While it is currently located in Site-███ it may be transferred to a different site if approved by the site directors of both sites.
Description:
SCP-XXXX Is an entity that has different states of being depending on the level of light they are exposed to, these different states have been designated SCP-XXXX-A, SCP-XXXX-B and SCP-XXXX-C. It was found in a cave in the middle of █████████ , Texas, USA after there were reports of people going into the cave and not coming back, the bodies were located alongside the SCP.
SCP-XXXX-A: Safe
Between 720 and 980 lumens SCP-XXXX acts and resembles a human male, around 5'11" in height and weighing around 180lbs with short, blonde hair and blue eyes, however this entity does not seem to resemble anyone of any significance to the foundation, in this form SCP-XXXX seems to be very passive, despite it's situation it seems happy to cooperate and even interact with staff in a mild mannered fashion it will often answer questions as honestly as it can, it also seems to display a dislike for SCP-XXXX-B and SCP-XXXX-C, it has also informed staff that it's name is "Brian" however it has also said that it does not mind being referred to as SCP-XXXX-A as it understands it's own situation very well.
SCP-XXXX-B: Shadow
If the light level drops below 720 lumens SCP-XXXX changes state and morphs into a shadowy mist, while at first it usually resembles a large, unknown creature it is noted that due to it's non-solid nature it can change this form at a will, making it easy for it to escape containment, while SCP-XXXX is in this state it is a large danger to all staff within the facility, it has been observed using air-vents to escape and manoeuvre around the facility, while in this form it attempts to avoid all light sources as shining a light above 720 lumens onto it will cause it to change state, shining a light between 720 and 980 lumens onto SCP-XXXX-B changes it's state back into SCP-XXXX-A. It is also noted that SCP-XXXX-B kills by enveloping the creature, however the exact cause of death is unknown as there are no external or internal injuries on the victim after they are killed.
SCP-XXXX-C: Plasma
If the light level rises above 980 lumens SCP-XXXX will change state and morph into a bright bipedal creature around 7'2" in height who burns at approximately 3872 Kelvin, this creature, while very passive, is a huge threat to the structure of the facility and to staff due to it's extreme heat, it has also been seen being able to manipulate light around it, the extent of this power is unknown, however it is believed that if SCP-XXXX-C were exposed to the sun it could cause an end of the world scenario. Due to it being able to manipulate the suns light into going out, or even having the light be absorbed into itself.
