The AI entities could refer to some sort of blob or dynamic matter. According to our newest staff member Pinky, this blob can perform several actions such as drain itself possibly into a drains or sinks. There has also been found to be another AI entity called ‘Aperture: Nest’ however it is currently uncertain what this could be.
Here’s a screenshot:
In the meantime it appears that there is a large discussion on the Steam forums so maybe we can expect some more information sooner or later.
I would like to thank Pinky from Capture The Hill for discovering this story.