Per 
Item #: SCP-XXXX
Object Class: Euclid
Special Containment Procedures: is to be sealed in a steel box, which is not to be opened in the presence of female staff members, for the fear that it might latch onto them. The box used for containment is not airtight at the moment, but depending on how small SCP-XXXX can become, that might be necessary in the near future.
Description: SCP-XXXX is a parasitic lifeform of unknown intelligence. SCP-XXXX's lenght varies from 0,6 mm to 1 meter, although it is currently unknown how small it can shrink to. It’s length depends on how much and when it has eaten. SCP-XXXX has 4 legs, sharp teeth, and a tail, all visible in ultrasounds of hosts.
SCP-XXXX's hosts are always pregnant human females. SCP-XXXX enters their womb by eating though the skin, leaving an entry wound similar to a mosquito bite. When the parasite comes into contact with amniotic fluid, it expands at a fast rate. Then SCP-XXXX will latch onto the fetus, consuming it, and assuming its position, going as far as feeding from the umbilical cord. SCP-XXXX will start to expand at the same rate as an normal unborn human fetus.
When the host body of the parasite goes into labor, SCP-XXXX will start eating it's way out of the female host, and consume all it's flesh, growing rapidly. Then it will find a dark, dry place to hibernate in. While it is hibernating SCP-XXXX is in a comatose state, but is still able to lay its eggs. The hibernation phase lasts from anywhere between 3 to 5 months, during which SCP-XXXX shrinks notably. After the hibernation phase it will find another pregnant female to be it's host body.
All attempts to surgically remove SCP-XXXX from a pregnant host have so far been unsuccesful, and have led to the deaths of the host bodies.
The foundation is currently only in possession of 1 SCP-XXXX, however it is estimated that there are anywhere between 30 to 6000 instances of SCP-XXXX in the world. The reason for the foundation’s failure to contain more than 1 SCP-XXXX is that most cases go unreported and unnoticed. SCP-XXXX is also highly aggressive while feeding on the host's body, and it is recommended to wait for it to start hibernating, before attempting containment.
Addendum, cases:
There have been multiple reports of SCP-XXXX, and mentions of it range as far back as in texts written in ancient greek, in which it was described that "cursed" women gave birth to demonic children, that proceeded to attack people. They were described as having sharp teeth, and a tail, fitting the description of SCP-XXXX. There have been many other reported and unreported cases.
One of the most notable cases happened in █████. Doctors had realized that there were some abnormalities with the unborn fetus, most notably a tail. The foundation heard about this case after a news article briefly detailing how a 38 weeks pregnant woman had gone missing, and her skeletal remains had been found 65 hours later in her own apartment. The article described it as a gruesome murder, not giving away details that something anomalous would have been involved. The foundation had all articles related to the incident later removed. SCP foundation personnel searched the apartment, and found SCP-XXXX hibernating in the closet.
