"What..." O5-8 asks carefully, "would happen if we did know?"
"It would happen to you as well," Marion says, levelly. "...As for the rest of your questions: we manage that pharmaceutically. You know we have class-A amnestics, for people who very badly need to forget things? Of course you do. Who could forget about class-A amnestics? Well, in Antimemetics, we have a different pill, for people who need to remember things that would otherwise be impossible to remember. Mnestics, class W, X, Y and Z. Same Greek root as the word 'mnemonic'. The M is silent."
In her bag, her phone beeps again.
With a nod of approval from the O5, Marion reaches into her bag and turns her phone off, acknowledging the prompt this time instead of postponing it. She pulls a blister pack from another pocket and pops a pill out. It's hexagonal, and green. She holds it up, and is satisfied to see a flicker of recognition on O5-8's face. He's beginning to put it back together.
Marion says, "These are class W mnestics, the weakest, suitable for continual use. Two pills per day. Go down to the site pharmacy and ask. The pharmacist will claim they don't stock any such thing; they're misremembering, tell them to double-check."
O5-8 sighs. "And now, I think, I get it. I see why we're having this conversation at all."
"Yes," Marion says, popping a second pill out and handing it over to him. "It's because you missed a dose. You're supposed to be on these, the same as me and everybody on my staff. It's the only way we can work. You forgot to take a pill, and then you forgot all the information that the pills were helping you retain. You forgot why you were taking them, who gave them to you, where to get more. You forgot about me, and my entire department. And now I have to bring you up to speed."
"And if I take this," O5-8 says, "I'll remember this whole conversation and we won't have to have it again?"
"Hopefully not," Marion says.
Clay pipes up. "Uh, should I be taking those?""Sorry, kiddo," O5-8 says. "Need to know. Maybe when you're an O5 yourself." He swallows the pill. Marion swallows hers too.
"So what is SCP-055?" O5-8 asks.
"SCP-055 is nothing," Marion says, now relaxing entirely. "SCP-055 is, as described in the file, a powerful information autosuppressor. As far as experimentation has uncovered, it can only be defined in negative terms. We can only record what it isn't. We know it isn't Safe or Euclid. We know it isn't round, or square, or green or silver. We know it isn't stupid. And we know it isn't alone. But what we do know is that it's weak. It's weak because it's the only antimemetic agent in our possession which has a physical entry in the files. We have paper records of the thing. We have containment procedures. It's not Safe, which means it's dangerous... but it's contained."
O5-8 blinks. "You have procedures? Where?"
Marion points at her head.
"Then how many other antimemes are there? How much more dangerous do they get?"
"Ten that I know of," Marion says. "Statistically, probably at least five more that I don't know of. This does not count the antimemetic entities freely roaming the halls, not under containment. There are at least two in this room with us right now. Don't look. I said don't look! It's pointless!"
O5-8 does an impressive job of controlling himself, keeping his attention focused on Marion. Clay doesn't fare so well, and quickly sweeps the whole room, even checking behind his back. Making an ass of himself, essentially. He finds nothing. He looks baffled.
"There is an invisible monster which follows me around and likes to eat my memories," Marion explains, patiently. "SCP-4987. Don't look it up, it's not there. I've learned to manage with it. It's like a demanding pet. I produce tasty memories on purpose so it doesn't eat something important, like my passwords or how to make coffee."
"And what's the other one?" Clay asks.
With another nod from O5-8, Marion goes to her bag again. This time she pulls out a gun and shoots Clay twice in the heart.
More aghast than in pain, Clay collapses sharply against the bookcase behind him. Pulling his head around to face Marion, he manages, "How did you— kn—"
Marion stands, aims more carefully and shoots him a third time, this time in the head.
O5-8, again, does an impressive job of not reacting. "That's Clay's gun," he deadpans. "You stole it from him."
"It's tricky to steal a firearm this heavy from someone without them noticing," Marion explains, unloading it and carefully setting it down. "But stealing a firearm and then stealing their memory of the theft is a little easier. Like I said: a pet. Some pets are dumb enough that they can be trained."
"Yes," O5-8 says, evenly. "That much I'd guessed. But why?"
"Because you were supposed to be taking class-W mnestics," Marion says. "You can't skip a dose of class-W mnestic. I've tried. You can postpone a dose, but you can't forget unless someone actively prevents you from taking it. There's only one person who could get close enough to you to do that, and that's your assistant. And remember when I asked him how long he'd been working here?"
"He didn't answer," O5-8 says. "I thought you were being rhetorical."
"He doesn't work here," Marion says. "He's an antimeme. Since when do you have an assistant? You don't have an assistant, Brent. Look at this office. It's got one desk. You've got a receptionist outside: she's the one who screens your calls and schedules your meetings. Where does Clay even sit? Where does he fit? Don't blame yourself. You're human, and these things are redaction incarnate. You need to think like a space alien to get around them."
O5-8 asks a question which, in any other workplace, would be absurd. "Is he dead?"
"Maybe," Marion says. "I can put his corpse in our research queue and we'll see what we can see when we open him up. There's a duality here, though. They're like parallel universes sharing the same space. It's conceptual versus concrete, figurative versus physical. It's very unusual for things to cross over. I don't know what Clay was, but he had a human body, which instantly makes him weird, even by our standards. As ever, the search for stalemate continues. I will let you know if we get any closer."
"Any side effects of these pills?" O5-8 asks.
"Nausea, and dramatically increased risk of pancreatic cancer," Marion says. "And very bad dreams."