SCP-106 appears to be an elderly humanoid, with a general appearance of advanced decomposition. This appearance may vary, but the “rotting” quality is observed in all forms. SCP-106 is not exceptionally agile, and will remain motionless for days at a time, waiting for prey. SCP-106 is also capable of scaling any vertical surface and can remain suspended upside down indefinitely. When attacking, SCP-106 will attempt to incapacitate prey by damaging major organs, muscle groups, or tendons, then pull disabled prey into its pocket dimension. SCP-106 appears to prefer human prey items in the 10-25 years of age bracket.

SCP-106 causes a “corrosion” effect in all solid matter it touches, engaging a physical breakdown in materials several seconds after contact. This is observed as rusting, rotting, and cracking of materials, and the creation of a black, mucus-like substance similar to the material coating SCP-106. This effect is particularly detrimental to living tissues, and is assumed to be a “pre-digestion” action. Corrosion continues for six hours after contact, after which the effect appears to “burn out”.

SCP-939 are endothermic, pack-based predators which display atrophy of various systems similar to troglobitic organisms. The skins of SCP-939 are highly permeable to moisture and translucent red, owing to a compound chemically similar to hemoglobin. SCP-939 average 2.2 meters tall standing upright and weigh an average of 250 kg, though weight is highly variable. Each of their four limbs end in three-fingered claws with a fourth, opposable digit, and are covered in setae which considerably augment climbing ability. Their heads are elongated, devoid of even vestigial eyes or eye sockets, and contain no brain casing. The jaws of SCP-939 are lined with red, faintly luminescent fang-like teeth, similar to those belonging to specimens of the genus Chauliodus, up to 6 cm in length, and encircled by heat-sensitive pit organs. Eye spots, sensitive to light and dark, run the length of their spined dorsal ridges. These spines may be up to 16 cm long and are believed to be sensitive to changes in air pressure and flow.

SCP-939 do not possess many vital organ systems; central and peripheral nervous systems, circulatory system, and digestive tract are all absent. SCP-939's respiratory system is atrophied and serves no apparent purpose beyond spreading AMN-C227 (see below). SCP-939 have no apparent physiological need to feed, nor any way to digest consumed tissue. Ingested material typically accumulates in the respiratory system of SCP-939 and is regurgitated once the amount is sufficient to markedly inhibit its function. Despite the absence of many vital organ systems, SCP-939 are capable of bearing live young. 

SCP-035 appears to be a white porcelain comedy mask, although, at times, it will change to tragedy. In these events, all existing visual records, such as photographs, video footage, even illustrations, of SCP-035 automatically change to reflect its new appearance.

A highly corrosive and degenerative viscous liquid constantly seeps from the eye and mouth holes of SCP-035. Anything coming into contact with this substance slowly decays over a period of time, depending on the material, until it has decayed completely into a pool of the original contaminant. Glass seems to react the slowest to the effects of the item, hence the construction choice of its immediate container. Living organisms that come into contact with the substance react much the same way, with no chance of recovery. Origin of the liquid is unknown. Liquid is only visible from the front, and does not emerge or is even visible from the other side.

SCP-682 is a large, vaguely reptile-like creature of unknown origin. It appears to be extremely intelligent, and was observed to engage in complex communication with SCP-079 during their limited time of exposure. SCP-682 appears to have a hatred of all life, which has been expressed in several interviews during containment. (See Addendum 682-B).

SCP-682 has always been observed to have extremely high strength, speed, and reflexes, though exact levels vary with its form. SCP-682's physical body grows and changes very quickly, growing or decreasing in size as it consumes or sheds material. SCP-682 gains energy from anything it ingests, organic or inorganic. Digestion seems to be aided by a set of filtering gills inside of SCP-682's nostrils, which are able to remove usable matter from any liquid solution, enabling it to constantly regenerate from the acid it is contained in. SCP-682's regenerative capabilities and resilience are staggering, and SCP-682 has been seen moving and speaking with its body 87% destroyed or rotted.

 SCP-076 consists of two components: a stone cube (SCP-076-1) and a humanoid entity contained within (SCP-076-2).

SCP-076-1 is a 3 m cube made of black speckled metamorphic stone. All surfaces outside and within SCP-076-1 are covered in deeply engraved patterns corresponding to no known civilizations. Radioisotope analysis indicates that the object is approximately ten thousand (10,000) years old. A door is located on one side, sealed with a lock 0.5 m in width, surrounded by twenty (20) smaller locks in a circular pattern. As of yet, none of the keys have been found, making the door impossible to lock once closed.

Interior temperature is approximately 93 Kelvin, and cannot be altered by any means, internal or external. Directly in the center of the room is a 2.13 m tall stone coffin, held in place and sealed shut by several chains of unknown make and substance, which are attached to the inner corners of SCP-076-1.

SCP-076-2 resembles a lean Semitic human male in his late twenties. Hair is black, and eyes are gray, skin tone olive. Subject is 1.96 m in height and 81.65 kg in weight. Numerous tattoos depicting arcane and occult iconography are present all over the body (mostly in the form of leering demonic faces) and ranges from subtle to openly ostentatious. Subject, when encased inside SCP-076-1, is technically dead.

However, occasionally SCP-076-2 will awaken, effectively "reanimating", complete with all vital processes needed to sustain a living human being. Subject will then attempt to leave SCP-076-1. If successful, subject will enter a trance state and seek out the nearest human being, ignoring all other living things in the process. Upon coming into contact with living humans, SCP-076-2 will enter a rage state in which it attempts to engage and kill all human beings encountered. To date, only the subject's death has been shown to be effective in ending these rampages.