Tendrils.

SCP-031 tendrils terminate in a pod-like structure (sporocarp) consisting of an ovoid structure approximately two meters in length, with multiple cilia-like structures branching off of the main body. On some occasions, subjects in the presence of an SCP-031 sporocarp will instead perceive it as an individual the subject had a close emotional connection to in their past. The SCP-031 sporocarp will metamorphose into the shape of the person perceived, and attempt to persuade the subject to remain with them for an extended period of time.

The SCP-031 sporocarp will next attempt to make physical contact with the targeted individual with their cilia-like structures. Digestive juices will be injected into the subject's body, and their flesh will be consumed and incorporated into SCP-031's body mass. In the meantime, a secondary flagellum will engulf the subject's cranium and brain, replacing the blood vessels with its own tendrils, which will maintain life support of the affected brain by some yet-undiscovered means. The tendrils will decerebrate the subject and transport the subject's cranium back through the building's ductwork where it is incorporated into the central mass.

Footage taken through surveillance drones indicate that there are currently █,███ crainia in the network of tendrils attached to SCP-031's central mass. By all indications, the brains contained within are still alive, and may be conscious.