Gwen was frozen for a moment while she tried to find her voice. "What? What do you mean you don't remember? Jack. You were there. You were with me the whole time, what happened?"

"I don't know!" Jack growled with frustration. "And every time I stop thinking about it I forget all over again." He slammed his hand down on the table and immediately regretted it, both for the pain now throbbing through his fist and the fact that the noise probably reached the medical bay.

"Okay, just – just calm down." Gwen tried to rationalize. "What's the last thing you remember before finding the Doctor?"

Jack thought hard, kneading the palms of his hands into his forehead. "I remember…I remember getting the message on the computer. I remember driving to the house, or whatever it really is, and standing outside the cellar and hearing –" He swallowed heavily as he remembered the thick thud sound the Doctor's head made when it hit the stone wall and the shouting that had followed – "Then I remember opening the cellar door and…" He made a vague gesture with his hand. "And then the Doctor's waking up, and it's just you, me, and him down there."

"You don't remember the man?"

He pounded his head harder, not caring about the headache he was beginning to get. "No…no, I do remember a man," Jack said uncertainly. Then he let out another growl. "But that's it! I don't know what happened to him, where he went… And Ianto said you said something about a blue light coming out of the body, and just now something about how it vanished through the ceiling, but according to my memory circuit that's a load of crap, except for that my own crap doesn't make any sense either!" He felt like tearing the hairs out of the top of his head and grinding his teeth down to stumps if that would just help him to remember.

"So…so, you don't remember the feeling then?" Gwen asked uncertainly, sinking into a chair of her own. Looking into her eyes, Jack could tell she was desperate for him to confirm what she'd felt and seen. He could also see the raw fear she was trying to hide and felt a shiver run up his spine.

"I was scared." He realized. "More scared then I'd ever been in my entire life. But I'd just found my best friend chained to a wall, so who wouldn't have been?" He tried to rationalize.

Gwen sighed. "I'm sorry, Jack, but I don't think that was the cause."

"What do you mean? You think I was scared of that – that – whatever it was?" Jack snorted as if to say that the thought was ridiculous, but even he wasn't entirely convinced.

One of Gwen's eyebrows arched up. "Yes, that's exactly what I think." She said bluntly. "Because that's exactly what happened to me. And no offence to him, but I'm not quite close enough to the Doctor for that to be the cause for me, too."

Jack put his head in his hands and briefly wished he'd taken Martha's instructions to go to bed. His headache was escalating with each second and he wasn't liking this conversation. "Okay, so, let's jog my memory. Step-by-step, what happened after we entered the cellar?"

"Well," Gwen began. "We pulled open the cellar doors and you jumped down first. All we could see was the man's back as he was holding the Doctor by the neck. You shouted something and he turned around and…his eyes –"

"Stop!"

Both Jack and Gwen jumped at the new voice, having thought they were alone. Jack spun around in the direction of the familiar voice. "Doctor! What the hell are you doing?"

The Doctor was standing in the doorway leading towards the medical bay, clinging onto the doorframe desperately for support. With a quick shove he lunged towards the stairs, grabbing at the metal railing and giving a shout of pain as he tried making his heavily wrapped legs move.

"Jesus," Jack muttered as he rushed forward. He jumped down the stairs and took the Doctor under the arms, twisting him around so he could sit on the steps. The Doctor groaned again as his injuries protested to the movement and there was a thin sheen of sweat on his forehead from the effort of getting to the main hub. "Doc, you're supposed to be resting." Jack scolded.

The Doctor gave a breathless laugh "Yeah, and so are you. Seems like neither of us are listening to Doctor Martha's orders tonight." He tried to turn around, wincing, trying to look for Gwen. "You have to stop." He ground out between clenched teeth, his voice barely louder than a whisper.

Gwen stepped forward so she could hear him better. Her eyebrows were knitted together in confusion, mirroring Jack's. "Stop what?"

"We'll stop talking about it if it's bothering you." Jack supplied quickly, but the Doctor was shaking his head.

"No. No. You have to remember." He said breathlessly. "You have to stop talking about him so you can remember."

Jack exchanged a puzzled look with Gwen. "Doctor," He said slowly. "You're not making sense. You need to be resting. Your legs are broken, how'd you even get out here!"

The Doctor ignored him. "Gwen, what are all the lyrics to Rocket Man? It's important, I swear."

"Umm…" Gwen looked completely taken aback. "I-I don't know, I'm not really an Elton John fan…"

The Doctor made a surprised face. "Really? Shameful! Elton's such a dear. AH!" He clutched at his leg, which he'd been trying to pull up the steps but had accidentally rammed it into the side instead. He wasn't used to moving them again just yet. "Okay, then what you need to do is look up the lyrics, memorize them, and then come recite them to me, okay? Quickly! Go Gwen."

After shooting a how-the-hell-is-this-important look at her boss, Gwen hurried off to one of the computers, pulling up a search engine. Jack turned back to the Doctor, an eyebrow raised, asking the same question Gwen had just silently asked him. The Doctor laughed shortly.

"Just had to get her thinking about something else." He answered the look. "Anything else really, and Rocket Man's been stuck in my head for the last millennia."

"Why?"

"It's a great song. Come on, don't tell me you're not an Elton fan as well."

"No, Doctor, I mean, why can't she think about it?"

The Doctor's face fell instantly. Jack noticed he was beginning to shake again, even if it was just a tiny tremor, almost undetectable. "Because that's how he works." The Doctor's voice cracked ever-so-slightly when he mentioned him.

"It's alright, Doc. You don't have to talk about him if you don't want to."

"No, y-you should know anyway. N-not talking about him is n-not going to make it better any f-faster." Damn, the stutter was back. The Doctor closed his eyes, and when he opened them Jack was startled to see that they looked darker somehow, even more haunted then before. The Doctor took a steadying breath before starting, his voice low and slow as he tried to keep the ineffable fear at bay.

"The creature's called a Metmorsus. They're from a small planet in the Calypsian Galaxy, a system known for raging vicious wars and rivalries between the civilizations. Thankfully they've yet to reach out into other galaxies, so it's pretty contained. But," The Doctor hesitated slightly. "But the Metmorsi… they were born of the fear and pain of war, and that sort of thing has an effect on a being."

Jack remembered when he'd first met the Doctor all those years ago, how he'd said he'd been 'born of the Time War'. Obviously he had meant that one body, and thankfully Rose had been helping him through it, but he kind of had an idea of what the Doctor was trying to say. Or at least he thought.

"It's what they thrive off of." The Doctor continued with a hint of venom in his quiet voice. "Pain and terror. For a while it was enough just feeding off the results of war, but then they started getting hungrier, to the point where they had to start causing it just to satisfy themselves."

Nevermind, Jack thought. That was definitely not the direction he had been expecting the Doctor to take.

The Doctor swallowed. "They – they need the fear. Not just for entertainment, although there is that too, but to survive. It's part of their basic genetic build. You c-can't really blame them for it then,"

"Just watch me." Jack growled.

"But that's part of their defense. They have minor psychic abilities, just enough to get into your head and trigger the fear sensors of your brain, making you experience a rush of crippling terror just by looking at them. And then they make you forget about them…but not what you just felt. Because it's more terrifying to be afraid and not know why."

Jack shivered. He believed that theory, too, because he was experiencing it right now. "So why does that mean we can't think about it?"

The Doctor sighed. "It's like…it's like trying to remember a dream after you wake up. The more you think about it, the more you try to piece it together, the faster the images seem to slip through your fingers. It's like trying to hold water in the palm of you hand. You've just spent the whole day trying to figure out what that thing was in the cellar, and now you've found that you can't even remember it."

"So how come Gwen can?"

The Doctor shrugged. "Maybe she's been focusing on something else ever since." He suggested.

The house, Jack realized. Gwen must have been too focused on the house and finding its owner to think about what the man was. "So then why are you telling me this now if I'm just going to forget again?"

"No, it doesn't work like that." The Doctor said, shaking his head. "If I tell you, you'll remember, but it you experience it, you'll forget."

"So how come you remember?" Jack asked carefully.

A shadow passed over the Doctor's features. "Two years isn't something you forget easily." He answered darkly. "But someday I will. The fear it makes you feel is like a drug: eventually it'll run its course and burn out of your system, and the longer you're exposed to it the stronger it is and the longer it lasts. You only saw him for a second, that's why you're forgetting so quickly. Since I was there so long it'll take a while for it to completely leave me, and with it it'll take the memory. And that's the really scary part." His eyes were suddenly very far away and seemed almost black, and his voice had taken on a heavy tone. "One day, I'll wake up with all these scars and all this pain, and I'll have no idea why."

TBC

A/N Shorter chapter for you guys, but now you know what that thing was….or is.

Also, I've been on spring break this last week and a half (hence all the updates) but next week I'm back in University and have midterms, so it might be a while before the next chapter is up. Just apologizing in advance. Hopefully you can forgive me in advance. Have you ever tried writing while guilty? It's not pretty…