Item #: SCP-2171
Object Class: Euclid Safe
Special Containment Procedures: All areas affected by SCP-2171 are to be placed under permanent video surveillance and / or botanical field supervision, on a case-by-case basis.
New instances of SCP-2171 should be subject to a thorough botanical analysis and, when necessary, restored through environmental engineering operations conducted by Containment Task Force ϱ-6 ("Green Gale") personnel.
During seasonal autumn and until the demanifestation of all SCP-2171-1 entities, areas affected by SCP-2171 are to remain closed to all civilian transit.
Description: SCP-2171 is a seasonal phenomenon involving the fallen leaves of all deciduous trees rooted within the confines of certain areas (henceforth, "the area").1 Leaves fallen within the area during seasonal autumn will invariably form large piles that will remain unaffected by local weather until all deciduous trees are completely defoliated. Piles of leaves affected by SCP-2171 will slide slowly, forming "windrows" of varying width. These SCP-2171 windrows will eventually manifest instances of SCP-2171-1 at their front end.
SCP-2171-1 are humanoid entities composed entirely of SCP-2171 affected leaves that appear to "guide" the SCP-2171 windrows. SCP-2171-1 entities are fragile but capable of movement, yet apparently impervious to hostile weather conditions. SCP-2171-1 emit repetitive vocalizations that may involve speech in various languages (see Addendum 2171-02) and have a tendency to hook dried leaves on tree branches across the perimeter of SCP-2171 areas or string leaves between trees that delineate this perimeter.
Given its behavior, SCP-2171-1 are currently suspected to be sapient. However, SCP-2171-1 instances will only react when the integrity of the SCP-2171 windrows they grow from is compromised in any way.
SCP-2171-1 will react violently against any element disrupting the SCP-2171 windrows. Such reaction will include various vocalizations in a much lower pitch (see Addendum 2171-02), a considerable growth in size by drawing mass from the SCP-2171 windrow to which the entity pertains and persistent attempts at enveloping the disturbing element in a thick cover of SCP-2171 affected leaves. Once covered, the element will appear to dematerialize, being replaced by a similar volume of fallen leaves.
SCP-2171's anomalous properties will typically disappear after two or three days of continuous activity.
Addendum 2171-01: Environmental status in Locations of Interest affected by SCP-2171.
Addendum 2171-02: Registered vocalizations from SCP-2171-1 (extract).