Per 
Special Containment Procedures: A Foundation-operated patrol craft masquerading as a naval vessel belonging to the relevant regional government is to patrol in proximity to SCP-XXXX and turn away ships attempting to approach the source of the signal.
If SCP-XXXX becomes known to the public, a disinformation campaign is to be conducted portraying it as a form of encrypted military communication.
Description: SCP-XXXX is a recurring intermittent radio signal which is broadcasted at random from a point in the Pacific ocean. One source of the SCP-XXXX transmission exists at a time, emitting continually for a period of 3-6 months before disappearing and reappearing elsewhere within two years. SCP-XXXX typically takes a frequency of 8-16 kHz.1
SCP-XXXX’s signal strength varies between appearances, with a historical high of 31.94 dBμ2 Triangulation of SCP-XXXX’s origin gives a specific latitude and longitude. However, exploration of those coordinates does not reveal any source for the signal on the surface. Instead, SCP-XXXX originates from an indeterminate depth below sea level, anomalously penetrating several kilometres of ocean water with minimal attenuation.
Addendum XXXX.1: Exploration - Synopsis
SCP-XXXX was first discovered by an American naval vessel in 1926 when the signal was acquired by an incompetent radio technician operating outside of sanctioned frequency ranges. Since then, a number of investigations into the anomaly have been undertaken.
In 1956, a British Royal Navy vessel attempted to produce a map of the seabed around SCP-XXXX via a towed sonar transmitter. The attempt failed because the sea floor could not be located. In 1985, the Foundation became aware of SCP-XXXX as an anomalous phenomenon and dispatched a submarine on an exploratory mission. After descending 6,440 metres, the submarine was forced to ascend without finding SCP-XXXX’s source. However, it was able to spot the mouth of a large trench in the ocean floor. Subsequent explorations, following SCP-XXXX’s relocation, were unable to locate this trench.
On the 13th of August 2012, SCP-XXXX appeared within the Bismarck Sea. A deep-sea submersible originally developed for containment of an unrelated anomaly3 was allocated for an exploration attempt. A four-man crew was assembled to dive over the signal’s point of origin. The submarine was redesignated DSV.XXXX.4 The expedition commenced on the 9th of September 2012.
Crew Manifest, DSV.XXXX
Junior Researcher Catherine Amy Vidicer: F / 48
Provenance: Volunteered.
Assignment: Catalogue discoveries.Technician Violet Addaway: F / 25
Provenance: Conscripted due to repeated misdemeanours, abuse of antidepressant medication, and poor workplace performance.
Assignment: Maintenance engineer.Agent Serie Iris: F / 39
Provenance: Conscripted due to behaviour unbecoming of an agent of the Foundation and dereliction of duty.
Assignment: Security and janitorial duties.Doctor Minerva Skye: F / 39
Provenance: Volunteered.
Assignment: Collect and examine samples.
Addendum XXXX.2: Exploration - Video Files
Security Footage | 1:55am 10/09/12 | Communications Room
Interlocutors: Agt. Iris, Dr. Skye
Depth: 9,865 metres, 1397 bar
(Begin Transcript)
Agent Iris enters the comms room. Dr. Skye is in the process of tuning the radio.
Skye: Hey kid.
Iris: Careful! That’s for Addaway’s hands only.
Skye: Relax, she taught me how to operate it, I’m not going to break anything. Speaking of, why are you here? Did her snoring wake you up?
Iris: I woke up on my own. Had another dream.
Skye: You want to talk about it? I used to be a shrink.
Iris: I don’t remember much. Just that I was alone in the water and something was watching me from below. Or maybe… listening. That- that feels a little more right. I’m telling you, there’s something down here.
Skye: We already knew that, else we wouldn’t be here. Were you afraid of the dark as a kid?
Iris: I still am.
Skye: There you go, that’s where the nightmares are coming from. We’re two leagues beneath the bathypelagic, of course your nerves would be shot.
Iris: Actually, I’ve had these dreams since forever. It’s only recently that they… clarified. Aren’t you scared at all, doctor?
Skye: No, I can’t say that I am. It’s kind of exciting, right? Being so far from the surface, hunting for something in the deep? If anything, I’m mostly worried that I’ll be let down by whatever we find.
Iris: Keep waiting. I’m going to wish for another day of silence.
Skye: Ask for a week while you’re at it. Who knows how long it’ll take to discover something worthwhile. I know Vidicer’s not turning back without results.
Skye turns up the volume on the radio. It plays a slightly more legible variation of the SCP-XXXX signal.5
Iris: Turn that off, it creeps me out.
Skye: I’m just curious as to what it is. The signal’s kind of melodic at times, don’t you think?
Iris: It sounds more like electronic chirping to me. Nothing decipherable. It doesn’t matter, who cares what it means.
Skye: Have you heard of 52 Blue? It’s a whale that sings at a frequency that no other members of its species do. Some call it the loneliest whale in the world. But it still keeps going, even after twenty years of isolation.
Iris: I don’t understand.
Skye: When I’ve got nobody around to fill the silence with, I sing too.
Iris: I’m taking some melatonin. Have a nice night.
Iris leaves the room. Skye begins humming. The wall opposite to the entrance creaks and bends inwards. Shortly thereafter it bursts and the room fills up with water.
Security Footage | 3:02am 10/09/12 | Medical Bay
Interlocutors: J.R. Vidicer, Tec. Addaway, Agt. Iris
Depth: 10,563 metres, 1423 bar
Addaway is sitting near the centre of the room, next to Skye’s body, which has been laid out on a gurney. Though soaked, the cadaver shows no visible signs of damage. The DSV’s primary radio module has been recovered and set aside. Vidicer and Iris stand around Addaway.
Addaway: I- I’m sorry, I don’t know what happened. I had an early night. If I had made the rounds one last time, maybe she would still be alive.
Vidicer: This submarine is meant to be serviced by a crew of twelve. You’re doing fine under the circumstances. It wasn’t your fault.
Iris: When you went outside to fetch Skye’s body, you saw the hole in the side of the ship. Tell me what it looked like.
Addaway: Round? It- it just looked normal to me. It wasn’t like an animal tore it apart or anything, it just looked like a regular mechanical fault. This isn’t really my area of expertise, I thought I just had to, you know, keep the engine fuelled, keep the plumbing running, that kind of thing.
Vidicer examines Skye’s body more closely.
Vidicer: No cuts, no bite marks, not even a crushed rib cage. Morbid but remarkable. Maybe it’s a property of the water outside? I wish we had brought some test animals.
Iris: Sharks can smell blood at concentrations of one ppm.
Vidicer: Come on, a shark didn’t tear a square metre hole in the DSV. Do you really listen to every hackneyed instinct that your dull lizard brain telegrams you?
Iris: It’s kept me alive this long.
Vidicer: Do you think the first man to reach the South Pole gave in to his anxieties? Read your history; fear isn’t a constructive emotion.
Iris: That explains why you’re hoarding alprazolam.
Addaway: I can’t listen to any more of this. Why are we even having this conversation?
Vidicer: I’m trying to make a point.
Addaway: But either way, what does it change? We’re going down, no matter what.
Iris: Someone is dead. That’s a good enough reason to surface.
Addaway: And then they’ll throw you right back down here because we didn’t get what they wanted.
Iris: They wouldn’t send the same team two times in a row.
Addaway: There’s nowhere to go but down, Serie. You aren’t trapped on a broken, obsolete derelict eleven kilometres below the surface of the sea because of your merits. We’re here because we’ve proven ourselves to be expendable. Failing on our first try will only reinforce their impression of who we are.
Vidicer: Are you feeling alright?
Addaway: No. It’s just… I-I spoke out of turn. I’m sorry, ma’am.
Vidicer: There’s no need to apologise. I know you’re under a lot of pressure. I’ll clear out an icebox for Skye’s body. Both of you, go back to bed.
Addendum XXXX.3: Exploration - Radio Logs
DSV.XXXX Radio Transmission Database
Notes: SCP-XXXX and random noise have been removed from the transcript.
09/09/12, 7:33 am - Addaway: Radio check.
09/09/12, 7:34 am - SCPS Kalliope: Roger. Loud but distorted.
09/09/12, 7:34 am - Addaway: Understood. Out here.
10/09/12, 1:57 am - Unknown DMR ID: (Indecipherable)
10/09/12, 2:49 am - Unknown: Hello?
10/09/12, 3:25 am - Unknown: I’m cold.
10/09/12, 3:53 am - Unknown: (Humming)
10/09/12, 3:56 am - Vidicer: Is anyone there? Answer me.
10/09/12, 3:56 am - Unknown: Some claim the darkness presses in, clamping as if given jaws.
10/09/12, 3:57 am - Vidicer: I heard you. There’s no point in hiding.
10/09/12, 3:57 am - Unknown: But it doesn’t press, it pulls.
10/09/12, 3:58 am - Vidicer: Talk to me. Don’t you want to be understood? How many secrets do you keep?
10/09/12, 3:59 am - Unknown: I thought it would be beautiful here. I imagined gardens of bones and eyeless leviathans coursing through the void.
10/09/12, 4:00 am - Vidicer: When I leave, you’ll be alone again. Forgotten. This could be your chance to be memorialised.
10/09/12, 4:02 am - Unknown: I was wrong. We were wrong, Cathy.
10/09/12, 4:03 am - Vidicer: Tell me what I’m missing. Why is this place so empty? Serie spies things in the water. She swears that you speak to her in her sleep.
10/09/12, 4:03 am - Unknown: Emptiness has no texture. We are within a maw without a stomach.
10/09/12, 4:04 am - Vidicer: Sometimes I see Addaway hunched over the radio, listening to the signal. To you, I think. She hears things that I can’t make out at all. Why don’t I see what they do?
10/09/12, 4:04 am - Unknown: The stars above are burning out. The ones below are rotting.
10/09/12, 4:05 am - Vidicer: I hoped to find something down here, something that no one else has had the determination to come in search of. Was I misguided? Am I everything that they say I am?
10/09/12, 4:05 am - Unknown: Now, I am alive in places and ways you will never understand.
10/09/12, 4:06 am - Vidicer: I guess you never hear about anyone who died looking for a reverie.
10/09/12, 4:07 am - Unknown: The signal was never meant as a lure. There is no singer, only the song.
10/09/12, 4:09 am - Vidicer: Please. Say something.
10/09/12, 4:09 am - Unknown: There is nothing here. I want to go back.
10/09/12, 10:43 am - Unknown: (humming)
(Extraneous records removed)
Addendum XXXX.4: Exploration - Maintenance Journal
9th of September
This ship is ancient. The engine pounds like tachycardia. The ballast tanks wheeze. It has nothing but vital organs - potential points of failure. I’m doing my best to keep the machine trundling along, but I’m fighting a losing battle.
Vidicer asked me to teach her how to use the sonar readout. I don’t think she really understands it, but I gave her a crash course to get her off my back. Now she spends all of her time mapping out the walls of the canyon. So pointless.
Still, I’ll do anything to appease her. I can’t lose this job.
10th of September
Skye died this morning. The walls shrieking woke me up. Now, heat is bleeding from the wound it left behind. At night I can feel the water pressing in on the DSV’s walls, as ocean currents struggle to form teeth.
Vidicer was up on deck all night, hawking the radio. She can’t hear the voice. Not like I do. She’s jealous of me, beneath that outward veneer of condescension. She tries to mask her insecurities, but it’s obvious why she’s here. Forty eight years old and she’s barely made junior researcher. She’s trying to earn a promotion. It’s so naive - I almost feel bad for her.
11th of September
Iris came to me in the middle of the night to demand that I take us up. She had a knife. I told her what to do in order to blow the ballast tanks clear of water. When she tried it, the tanks burst and flooded. We’re sinking faster, now.
I’m okay. No stab wounds for one thing. And for another, it’s peaceful down here. The rumble of the engines is like a second heartbeat. I haven’t needed my pills in days.
It’s strange to think that they all came here with something in mind. Vidicer, hoping to bring something back with her. Skye, looking for beauty in forgotten waters. And Iris, she came looking for answers. The source of all her nightmares.
I came here searching for nothing. And that’s exactly what I found, in a sense.
I think I’ll have a lie down.
Addendum XXXX.5: Exploration - EVA Suit Footage
EVA Suit XXXX.1 | 3:09pm 11/09/12
Interlocutors: S.R. Vidicer, Agt. Iris
The video is filmed from the perspective of the EVA suit’s bodycamera, which Iris is wearing. She navigates through the DSV, whose power is failing. The hallway is flooded up to Iris’ shins in water.
Iris navigates toward the airlock. Along the way, she passes by Vidicer in the sonar deck. The radio is beside her.
Iris: Catherine. I’m taking the suit and leaving.
Vidicer: Do you hear anything on the radio? A voice?
Iris: I hear someone humming.
Vidicer: All I can perceive is static.
Iris: I don’t understand it either. I wish I was as numb to it as you.
Vidicer: So we envy each other.
Iris: I guess.
Vidicer: (Laughs) I thought that there would be more than empty water down here. But the signal, it’s just meaningless noise. Never growing louder, never abating. Just… there. A point of fixation.
The monsters, the mystery, the dreams. We made it all up. We’ve been chasing our own imaginations.
Iris: Catherine?
Vidicer: You should leave.
Iris inspects a barometer. The readout is too high to be displayed.
Iris: I should.
Iris proceeds to the airlock, where Addaway is lying on top of a bench, apparently asleep. Iris reaches for the EV hatch, but hesitates as Addaway opens her eyes and looks up. Footage cuts out at this point.
Addaway was recovered unconscious from the waters above SCP-XXXX on the 13th of September, wearing the EVA suit. All records related to the expedition were drawn from its internal databank.
