Nights 1-7: Children will report seeing SCP-4666 in the vicinity of their family's dwelling. The entity will typically be observed watching the dwelling from a distance, such as from across a nearby field or from the edge of a neighboring forest. In some cases, children will report waking up at night to find SCP-4666 watching them sleep through a window.

Nights 8-11: Family members (including the parents) will report sounds of footsteps coming from the roof or the attic. An extremely unpleasant odor will also frequently be noticed inside the dwelling. No cause for these phenomena will be found. As a result, parents will often begin to suspect that their family is being stalked, or even that their dwelling might be "haunted".

Night 12: Over the course of the night one of two scenarios will occur:

The first, and most common, is that SCP-4666 will kill all members of the family save for one child under the age of 8, whom it will abduct. SCP-4666 will inflict incapacitating injuries to family members while they are sleeping, then herd them into a single room of the dwelling where it will proceed to kill them in view of each other. The method of killing varies with the event, and will typically be preceded by some form of torture, which appears to serve a ritualistic purpose (see "Weissnacht Events Log" below).
In the second scenario, which has occurred in roughly 15% of known Weissnacht Events, SCP-4666 will not harm the family. Family members will report hearing footsteps inside their dwelling during the night, though no signs of forced entry will be found. In the morning children will discover presents at the foot of their beds; these will consist of toys crudely crafted from the remains of human children (see "SCP-4666-A Instances Log" below).