The darkness is so deep that it seems to almost permeate into the pod. As he stares into the darkness, there is a few glimmers of bioluminescence in the distance. A handful of jellyfish are hurriedly swimming directly down, but they're shaped... wrong... There is an irregularity to the shape that no jellyfish has. As if some of them have been partially put into a blender and then been reconstituted as a living creature. 

They're quite far away, and the light is very dim, but for a moment he thinks he can see an eyelid open, revealing a very human looking eye, looking directly at him. Then the eyelid closes again and the jellyfish keeps swimming.

The sound of displaced water and cavitation keeps getting louder.

... concerning.

Ending up as some creature's lunch wouldn't help with the rescue, would it?

The sound has moved to directly above him now, and whatever was moving has now stopped moving. 

Then there's a vague pressure on the back of his head. And an itch behind his eyes. And a shiver down his spine.

Images of darkness and too many eyes and undulating flesh and tentacles appear superimposed on top of what he sees inside the pod. He hears wailing cries in the distance and a high pitched buzz and sounds of a disfigured mouth eating. On his skin there is the sensation of slime and scratches and electricity, but when he looks there is no wounds and no moisture except his suddenly appearing sweat. Then the pressure on the back of his head triples and he gets the distinct sensation of something pushing itself inside his mind. It wants to know you it wants to understand you it wants to show you it wants to communicate it wants to join with you it wants to create with you it wants to it wants to it wants to

What the.

Check oxygen level: good.

Check CO₂ level: good.

Check air pressure: nominal.

What the HECK.

Then suddenly the hallucinations cease, with a final impression of a wall of light appearing in the way of the stream of... something. Everything ceases, leaving only the memory of the supernatural experience and a lasting trace of the headache.

Some moments pass, and then the giant something above starts making noises of movement again, but this time slower and heading away from the pod, and making considerably less noise.

There is stillness again, though not silence. 

So that happened.

He's probably going mad. Pod fever?

There is a polite knock at the porthole, and a scaly face with red eyes patiently and solemnly peers in.

Who the what.

... sloooow handwave?

"Hi?"

A moment of taking in the motion, then a hand slowly raises, imitating the slow wave.

All motions are graceful and precise, eyes are intently observant. 

Uuuuh.

Points to himself. "Mark."

Only the lowest frequencies how his speech would make it through the hull into the water, but the pointing as a method of communication is an important building block to learn. So is the implication that identity is important to establish early in communication. The figure learns.

The figure points to itself in turn, mostly symbolically, and the mouth opens for a moment.

Since Mark seems to have calmed down slightly since the appearance, the figure takes some initiative.

A gingerly, slow, point toward Mark's head. A question maybe?

What with the head?

He still has some lingering headache, so he grabs his head with his hands and tries to mime that.

That is not what the figure means, but the figure does not know shapes for yes and no yet. Nor is there enough context to know that gesture means pain. 

Instead the pointing motion is repeated. And there is a decision to be clearer.

The figure leans forward, and the eye contact goes from intent to piercing.

There is a polite knock on Mark's brain.

:Hello?:

There is no response. But once his focus turns inward he notices a new affordance that is somehow related to the knock. Does he do the thing?

The piercing gaze remains but there is a continued stillness, as if not wanting to insist nor spook Mark.

Is he going insane? Probably.

Could he possibly resist poking the sparkly new thing in his brain? Absolutely not.

:Poke:

Something opens or is exposed or is let in. There is too much unmapped new stimulus, so the brain does what it always does and tries to map it to something already understood.

He gets the impression of someone walking into the kitchen module of a personal habitat, being careful to not touch or look at anything other than what is strictly necessary to sit down at the table in the chair across from him. He also gets the impression that the walls and floor and ceiling and insides of the cabinets and the environment outside the porthole are draped with his memories and experiences and thoughts.

There is the sense of a greeting, and since identity is important to establish early in communication, the figure conveys the task of caring for, or tending to a system.

Outside his mind, the Tender waves again.

Then the Tender indicates an affordance that is conceptually related to the first new one, but which seems inverted in valence. The Tender implores him to try it.

Teeeentative wave.

:Otherpoke:

The guest is swiftly evacuated. He is once again alone in his brain.

Body language is so intuitive to Mark that some was automatically absorbed during the brief visit. The Tender is currently testing the motions of nodding, shaking their head, and moving their face to various different expressions. Tries a couple things, while inspecting their own face in the reflection in the porthole, and then lands on a slight content smile, and a small nod. 

An offering gesture, but with a head movement and opened eyes in a way that implies optionality. And then another knock on the brain.

So. He can... invite Creepy Eyes into his brain and then... eject them?

Well. Not as if he has anything better to do.

:Invite:

Again there is a guest in the kitchen module. Again the Tender is very careful not to look at or touch anything not indicated.

The Tender mentally offers their hand as if to let Mark lead them, if he wants, and gestures to the memories and understandings and skills and knowledges and experiences draped across everything in the room. Is there anything he would like to show them?