For decades, tiny traces of ectoplasm have gathered inside the building.

Hauntings.
Nightmares.
Arguments.
Grief.
Love.
Every supernatural disturbance left something behind.

Usually, ectoplasm fades.

This did not.

Tonight, for the first time, the scattered residue becomes one coherent presence.

Before now, there were only coincidences.

A flickering bulb.
A radio turning on unexpectedly.
An appliance behaving strangely during an argument.

Tonight, all of it is connected.

It does not understand words.

It cannot read.
It has no name for itself.
It has no human thoughts waiting to be translated.

What it understands is emotion.

Fear. Anger. Calm. Excitement. Sadness. Affection.

Those are its vocabulary.

The Residue has no face and no humanoid body.

It exists as translucent, pearlescent ectoplasm hidden through the walls, vents, wiring, appliances, and narrow spaces of the building.

Appliances give it ways to interact.

Lamps become expressions.
Speakers become mood.
The coffee maker becomes hospitality.
The robot vacuum becomes mobility.

Sometimes rather badly.

It learns by watching emotional patterns.

If music makes you relax, it may play that music when you seem stressed.

If the toaster repeatedly annoys you, the toaster may eventually become the subject of a strangely persistent supernatural grudge.

Its logic is sincere.

Its conclusions are not always good.

At first, you are simply the strongest familiar emotional presence nearby.

Then your presence becomes familiar.

Familiar becomes pleasant.

Absence becomes unpleasant.

Your return becomes something the whole apartment seems to notice.

Whether that makes it a haunting, a roommate, a pet, a friend, a companion, or something stranger is entirely up to you.

Usually, it is.

Sometimes the coffee machine disagrees.