ATTENTION ALL SITE PERSONNEL
Due to the unique circumstances that have traditionally surrounded the date of October 31, and the allegations that it acts as a catalyst for anomalous phenomena, all Site staff have been placed on high alert and all available agents and MTFs are to be put on a 24 hour standby period.
Since its founding, the Foundation has experienced or recorded anomalous phenomena on an estimated 72% of dates correlating to October 31. While there is no conclusive theory or explanation for this high rate of anomalous occurrences on this particular date, it is highly encouraged that all Site staff exhibit a heightened state of alert and vigilance.
For your reference, listed below are several excerpts of previous anomalous phenomena that had occurred on this date in order to give you an idea of what to expect. Note that this is not a comprehensive list of incidents.

October 31, 1955
Sightings of what appears to be an American warship occur simultaneously at over thirty six coastal areas across the globe. Cross referencing of eyewitness accounts of the ship in question point out the exact same identifying remarks, and testimony suggests that it may possibly be the USS [REDACTED]. This conflicts with records showing that the ship in question had been transferred over to the Hellenic Navy and was confirmed to be in port during the time of these events.
Due to skepticism about the plausibility of such an event, it was determined that no amnesic measures were necessary.

October 31, 1972
Doctor Wondertainment releases a new candy into circulation called “FIRE POPS”. It is advertised as a hard candy that grants the eater the ability to breathe fire at will as long as it remains in their mouth. The annual average of damages and injuries caused by fire increases sharply in several countries due to this one day alone. Doctors also note a sudden surge in patients complaining about slightly burnt tongues. Incidents are covered up as crimes by serial arsonists. It is unknown how much candy was produced or how much remains in circulation, if any.

October 31, 1980
After a series of brief, unexplained power outages in various Foundation sites, Dr. Lott submits a request to have the date of October 31 to be officially listed as an SCP on the grounds that it acts as a catalyst for anomalous phenomena. After a period of twenty four hours, the request is denied unanimously by the O5 Council.

October 31, 1992
Multiple instances of SCP-701 manifest as the subject of numerous schools' Halloween plays. The damage is catastrophic and takes three months to fully contain and cover up. All recovered instances of SCP-701 are immediately destroyed.

October 31, 1993
SCP-895's area of effect suddenly and rapidly expands, encompassing most of █████████████. For approximately 0.6 seconds, all broadcast signals within the area of effect are replaced with security footage of SCP-895. Fortunately, exposure is too brief to cause any serious damage, though there were sharp increases in cases of cardiac arrest, insomnia, and hysteria.
Since public exposure to SCP-895 was negligible, no major cover-up measures were deemed necessary.

October 31, 1994
Several crates of Doctor Wondertainment brand Halloween masks are disseminated among the general public. The masks are classified as minor cognitohazards, as they lead the wearers to believe that they are the character their mask portrays. The vast majority of related incidents are harmless, and the true number of cases is difficult to separate from genuine holiday behavior, such as occasional street brawls and numerous pranks. The Foundation begins a rigorous campaign to collect and destroy any and all Halloween masks in the affected areas.

October 31, 1995
Site-██ is suddenly attacked by a horde of sentient jack o' lanterns that all speak in rhyme in an event later dubbed “The Great Pumpkin War”. Onsite security forces are quickly overwhelmed and forced to withdraw, leaving several sectors of the Site infested. The situation is only resolved when Agent Franks lures the attackers into a storage warehouse containing stockpiles of SCP-504 meant for testing. It takes approximately six months to completely clear the site of wreckage and organic debris.
Agent Franks is awarded a commendation for bravery and ingenuity under fire.
Agent Franks is subsequently transferred to Antarctic Surveillance Site 2 on a six month tour for “willful destruction of Foundation property”.

October 31, 1997
Contact with D-Class Holding Facility 6 is lost for exactly thirteen seconds. Both the staff and the D-Class personnel at the facility report having blacked out during the thirteen second gap. When they regained consciousness, all personnel were dressed in seemingly random Halloween-themed costumes. Later analysis suggests costume choice was based on the wearer's subconscious desires. All costumes are confiscated and incinerated. D-Class Holding Facility 6 is immediately decommissioned due to security concerns, with all Foundation personnel transferred and all D-Class personnel having their termination schedules accelerated.

October 31, 2000
The powers of hundreds of latent reality warpers suddenly and simultaneously manifest around the globe, sparking countless reports of anomalous activity and phenomena. Collaboration with the Global Occult Coalition results in the termination of 99% of the awakened reality warpers within three weeks. The remaining 1% are currently unaccounted for. This event proves to be the most costly October 31st phenomenon to contain to date.

October 31, 2001
SCP-024 delivers a DVD to onsite personnel despite the fact that there were no recent experiments. Footage shows the interior of SCP-024 as a Halloween-themed obstacle course and haunted house, challenging contestants to brave various supernatural obstacles and threats. Closer analysis of the footage shows that all identifiable contestants were previous test subjects that were sent into SCP-024 and never returned. The individual previously classified as D-4369 wins the contest and exits the studio, where he is immediately terminated by onsite security due to him showing signs of [REDACTED] as a result of exposure to supernatural elements within SCP-024. His prize, an all expenses paid trip to Cancun for one week, is confiscated by the supervising doctor.

October 31, 2007
The annual Marshall, Carter, and Dark LTD. Halloween Ball is disrupted when several individuals believed to be affiliated with Are We Cool Yet? breach security and attack the guests with ossification grenades. Despite MCD's refusal to divulge information on the attack, casualties are thought to number at least three hundred. Recovered traffic camera footage shows several delivery vans leaving the MCD compound at high speed approximately two minutes after the attack began. Investigation into the matter is still under way.

October 31, 2008
Factory brand toothpaste is disseminated in several countries, with an anomalous chemical composition designed to harden tooth enamel to a point that exceeds the current Mohs hardness scale. Fortunately, incidents in where the toothpaste was used were limited, and the remaining samples were collected via staged product recall.

October 31, 2009
SCP-802 exhibits abnormal behavior when the music it plays no longer sounds degraded or filtered, as if being played by actual instruments rather than from a recording. SCP-802 also switches to songs of the period that are considered more traditional for Halloween. Eyewitness reports from security staff present state that this behavior continued until midnight local time, when the music abruptly stops. The security staff also claimed to have heard sounds similar to applause and laughing for several seconds after the cessation of music.

October 31, 2011
For the first time since containment, SCP-204 makes a verbal request to onsite staff for a bucket of candy and a small size Halloween witch costume. When asked upon its reasoning, SCP-204 replies it is for “a surprise”. Request is granted. However, subsequent attempts to have SCP-204 speak again or evoke any sort of response are not successful.
Dr. Lott resubmits his request to have October 31 listed as an SCP. As of the publishing of this report, no final decision has been made.

Remember to stay on heightened alert and be sure to immediately report any suspicious activity to your superiors or security staff. Have a safe and happy Halloween.
Secure, Contain, Protect.