This isn’t me.

the setting is a apartment, the alien is a mental monster turning physical, it takes over a beings body and controls them, if the being is being taken over by the alien the creature will wrap its tentacles around the creatures body and implant themself onto the creatures black turning the taken over being skins red signifying the being has lost control over its own body, if the creature being taken over has enough control they can see still and if they have a amazing amount of control that can even subtly move their body parts potentially being able to take the creature out of them, the alien naturally attempts to take over the beings mind.