Per 
Item #: SCP-XXXX
SCP-XXXX-2 can be seen behind SCP-XXXX-1
Object Class: Euclid
Special Containment Procedures:
SCP-XXXX-1 is to be housed in a standard humanoid containment cell at Site-24. Subject is to be granted all requested accommodations and should be psychologically evaluated on a bi-weekly basis by project lead Dr. Bonny. Procedure GENETHLIAKON has to be carried out on the day before the subjects 18th birthday.
Site-24 has to be at least partially locked down on SCP-XXXX-1's birthday. Personell are to be prevented from perceiving SCP-XXXX-2 directly in any way on SCP-XXXX-1's birthday as this would constitute as an invitation and could trigger SCP-XXXX. Affected personell are to be terminated
Due to the nature of SCP-XXXX's containment efforts are to be concentrated on alternative modes of containment or the neutralization of SCP-XXXX-2.
Description:
SCP-XXXX is the designation given to the birthday party of a SCP-XXXX-1 instance. How exactly one becomes an instance of SCP-XXXX-1 is not entirely understood, there are however common denominators which seem to constitute eligibility. These are as follows:
- Western European
- 10 years of age, turning 11
- 11th birthday takes place on a saturday
- no siblings
- both biological parents are present in it's life
- lower middle class
- no physical illness
Additionally all instances of SCP-XXXX had the following factors in common:
- at least 6 guests attended the party
- the party took place indoors
- a birthday cake was present (the type of cake seems to affect the course of SCP-XXXX's events)
SCP-XXXX starts manifesting with the cutting of the cake and it's following consumption by all attending guests. After this point it is no longer possible to enter the building in which SCP-XXXX takes place. SCP-XXXX-2 will manifest shortly after and start to interact with the guests who at this point seem to have entered a trance. It will suggests party activities which get more extreme as time progresses. Over the duration of SCP-XXXX all attending guest will expire or suffer severe physical and mental trauma. After SCP-XXXX concludes SCP-XXXX-2 will manifest a small door on a nearby wall and lead SCP-XXXX-1 into an extra dimensional space hereafter designated SCP-XXXX-3. This space can be accessed afterwards, however doing so usually results in irreparable psychological damage.
Once SCP-XXXX-1 has entered SCP-XXXX-3 all subsequent birthdays of SCP-XXXX-1 will be instances of SCP-XXXX. The Subject will manifest a birthday cake and SCP-XXXX-2. All humanoids which perceive SCP-XXXX-2 will state that they have to attend a birthday party and will try to forcefully enter SCP-XXXX-1's vicinity. Should at least 6 humanoids enter SCP-XXXX-1's vicinity SCP-XXXX will trigger.
Addendum:
