Per 
Item #: SCP-XXXX
Object Class: Euclid
Special Containment Procedures: SCP-XXXX is to be kept in a 5x5cm un-openable metal case that does not allow any form of fluid to pass through it. SCP-XXXX is to be placed in the middle of a small chamber and kept inside the case (at all times) on a 2m-high pedestal made from tempered glass at all times. SCP-XXXX must be inspected every 4 days. SCP-XXXX cannot be handled by personnel with a clearance level lower than Level 3 clearance.
[SCP-XXXX on its date of discovery]
Description: SCP-XXXX has the physical appearance of a "mushed up mass consisting of nothing other than celery." After various testing procedures had been conducted on the object, it was found to have unexplainable capabities. Immediately after coming in contact with human saliva, SCP-XXXX begins to expand rapidly at a rate of 1 mile per hour. It is known to be capable of expanding to a distance of 2 miles in diameter in a circular formation before decreasing back to its original size. It can usually take about 1-2 months for the object to decrease back to originality, so containment procedures must be kept strict.
The entity's origins, although speculated, are unknown. The entity was discovered in a farmer's field in Devon, United Kingdom and was described to be 'pulsating' and around 5 meters in width and 6 feet in height. Upon its discovery, it was explained that the entity "had no apparent stench or aurora" however those who have been near it report feeling incredibly uneasy with 'the desire to step on it.'
It is unclear what SCP-XXXX is meant to embody, however studies show that it contains 95% water, insignificant protein and fat, and simply 1.4 starches. One investigator reported that 'if its behaviour, perhaps, wasn't so volatile, it could possibly be edible.' From an analysis, it was suggested that SCP-XXXX was simply an 'unexplainable and unknown moist mush of celery.' It is implied that SCP-XXXX has already been chewed repeatedly by an unknown entity which has simply been given the name SCP-XXXX-A which is believed to be the parent of SCP-XXXX and has not yet been identified or discovered.
Addendum: Since the object's discovery on ██.██.2020, five tests have been conducted and concluded. On the second test conducted by Dr. ███████ on ██.██.2020, a member of Class-D Personnel was instructed to expectorate their saliva on the object. Almost immediately after the object came into adjacent contact with the D-Class' sputum, it began to expand rapidly, destroying its annealed glass container in the process. After about 15 minutes, the object had grown so large (about 4 meters in width) that it had to be swiftly transported to an open area outside the foundation, where it continued to expand. The object's expansion concluded after about 2 hours and began to very slowly decrease. As of yet, no-one has tested what the object is capable of however it has been assumed that it is able to submerge and suffocate living things within its expanding mass.
The object reverted back to originality on ██.██.2020 and was immediately recontained. 3 more tests were conducted and concluded a month after this test and no new capabilities have yet been discovered.
All tests on the object have been halted due to its volatile and unpredictable behaviour and the likelihood that it is the offspring of something far larger. For now, the entity remains at 3cm in length and width enclosed in a 5x5cm zinc case that cannot be opened. This is intended to prevent the entity from coming into contact with human saliva or any other bodily fluid that perhaps could cause another unpredictable reaction from SCP-XXXX.
DOCUMENT CONDUCTED BY DR. ██████ ON ██.██.2021
