Originally, you had been alone.

It hadn't lasted long, at least, you weren't sure that it did. Time passed and moved but at what rate, you couldn't be sure. It had never mattered. It was all the same.

The Doctor did his work, and you were the subject for a while, but his frustrations only seemed to increase when he took you to The Room. You didn't respond quickly enough. You didn't understand. Sometimes you hesitated. You didn't handle what you were supposed to. You weren't strong enough. You were "willful."

You weren't a very good son.

So the visits slowed. He fed you, but he didn't take you to The Room. He hadn't given up on you, you thought. You were still being fed. He still cared. But why? You were bad. You didn't do good. You were fragile and weak and "willful,"whatever it was that meant.

But it's all you knew, so you wanted to be good and strong and obedient. You wanted the chance again. You wanted to prove yourself.

You didn't get the chance.

Instead, one day he brought them.

For the first short while, you hated them. Your replacement. You could tell they were strong. They were also much more open than you had ever thought to be. You assumed that was the difference between being willful and not.

They chattered on to you in the language you both knew and you didn't respond at first. You didn't want to talk. You didn't want to learn to like them, either. Then, when one of you was decided to be "unworthy," it would hurt much less. You thought that made sense.

The Doctor took you both back to do a check. Not to The Room, just to another area, one where he could monitor your progress and vitals, and he took you together. You weren't sure what the numbers meant, but theirs were so much higher than yours. They smiled of course, like they usually did, watching everything with curiosity and interest and never the slightest hint of fear.

You weren't afraid, either.

Neither of you had been fed yet. Visits to the The Room never happened on an empty "stomach." Neither of you had stomachs, as far as you knew, but that was the term the Doctor used, and he made you both, so he was probably right.

The Doctor seemed pleased, and you knew it wasn't because of you.

For a long time, neither of you went to The Room. The Doctor found a new type of testing and you made certain to excel in every way you could. You needed to be worth something. If you would only ever fail at the other tests, you needed to be able to pass these. You were very good at taking what the Doctor wanted you to do. The results he expected to see. You cheated any way you could.

"Isn't that bad?"

They were so obnoxiously loud.

They struggled with the tests. They knew these puzzles had special solutions, but they took the challenge at face value. They wanted to understand and make mistakes and enjoy them, which was stupid, insane.

"all that matters, the only thing that matters, is making the Doctor happy. and you make him happy by doing what he wants. don't be naive. the tests aren't fun."

"But they are fun! And wouldn't tricking the test make him mad?"

"only if he realizes it."

You tried to ignore them mostly. You didn't want to get attached. All the times the Doctor had told you he only needed one, that one didn't have to be you, you could be replaced. He could build something better. Well, here it was. Something better. Something that smiled like a dope (did your smile look like that, too? Neither of you looked like the Doctor. The Doctor was respectable, though, so you hoped you looked more like him than them).

They tried to get close. They were the sort that cuddled and hugged and talked and talked and talked for ages, eternities passing before they were finished, which didn't make sense because what was there to even talk about!? You both had the same experiences, only you had more. So what could they possibly be saying that they thought you didn't already know?

You ignored them.

The Doctor took them to The Room one day. They came back too quiet and didn't speak for the next two meals. They didn't eat, either, which you knew would make the Doctor angry, but better they learn the hard truths now.

Eventually they woke up from whatever stupor they were in. You didn't care for all the crying one bit. It was hard to care, when the Doctor's words constantly echoed through your skull.

"You can be replaced."

You never cried. And tears weren't anything the Doctor wanted or needed. He was replacing you with this? This loud, weepy thing?

"did it hurt?" You asked, knowing, of course, what the answer was. You weren't sure if you meant to be comforting or gloating. Whichever way your words landed was acceptable to you.

They nodded, slowly at first, then rapidly. So quickly that, had there been a brain in there, it likely would have sustained some damage, sobbing and grabbing onto you as if you were their only anchor. You were, so you let them hold you. They stayed like that all night, and you didn't try to stop them.

They returned to the Room again and you were starting to like them if only for taking on that burden entirely. They could withstand far more than you physically, even if they collapsed into a heaving ball as they did the night before. You were strong in that regard, at least. You'd never cried more than a little.

They came back with a blank stare again, vacant, the lights in their eyes gone. You could see evidence of rapidly-healed trauma. You had quite a bit of that, yourself. You felt bad for them, but it couldn't be helped, and you left them be until they inevitably started sobbing again. You didn't remember ever acting this way, but they hadn't seemed to realize the hours that had past the first time. Maybe you simply never realized when it happened to you.

It was like they'd been switched off, and it took a while to reboot. Maybe it helped with the pain?

Inevitably they snapped out of it. You thought that maybe it had taken longer this time, but you weren't concerned. You didn't care, remember?

You didn't care at all.

They hugged you and you let them, though you didn't return it.

You couldn't.

They were going to replace you. You were going to go wherever it was bad experiments went. You were weak, you were fragile, you were willful, you were stubborn and you were going to be thrown out with the trash as soon as this one had proven themselves superior. Once it was official. Once the data was clear. You were the one that was dying and they were the one that would live. If either of you deserved to be crying, it was you.

It happened again and again. They and the Doctor would leave, and their body would return before their mind did. It fell into a pattern, like clockwork, as you were left forgotten and alone and they swung back and forth between vacant and sobbing and vacant again.

The rations were slowly being cut back. The joke was on the Doctor, though, because your replacement had been missing meals anyway. Sometimes you were only given a single portion, and that portion went to you. You weren't going to share, and they weren't going to protest.

One day they came back from The Room with those lifeless eyes and never cried after. They went back to The Room with that blank stare. They came back with the blank stare.

It seemed the lights had gone out for good.

The Doctor would demand they eat, and so they ate when he demanded if. Otherwise, there was nothing there. The Doctor finally had his perfect, compliant creation. An empty shell.

He spoke to you both, but you knew he directed it to you, that you could be replaced. Try harder.

You weren't sure what you could be trying harder. He rarely tested you now. You just did as you always did, and silently dared him to finally end you.

They didn't do anything.

One day, they didn't come back from The Room. Not in mind, not in spirit, but not in body, either. They were just gone.

You didn't say a word, but during the next round of meals, you gathered up the courage to ask.

"Terminated. They were a failure."

And you were confused. Weren't you the failure? Weren't you the one they were going to replace?

Sensing your confusion, the Doctor chuckled.

"I need weapons. I need soldiers. I don't need puppets. WDGE002 was broken. Unresponsive and uncooperative. Weak."

You remembered that vacant stare, the one that grew and grew until there was nothing left of the person they had been.

You remembered the way you never held them, never hugged them back. Never touched them. Never listened. Never shared.

Never cared.

In turn, they'd had nothing to care about. No one to care for them. Not the Doctor. Not you.

So they stopped trying.

...

You were alone...

...

...

...

...

...

…Until you weren't.

Their replacement came. Small, loud and excitable, and you tried not to notice the recycled parts, the dents and scratches that you'd seen before and the grin and sockets you hadn't.

He never slept, he bounced off the walls and you swore to whatever and whoever might be listening, the Doctor, whatever bits of them might live on in the new one's borrowed vertebrae, and whatever force had built the Doctor himself, that this time you would care.

And when he stumbled back in from The Room for the first time, eyes deadened and booming voice silenced, you were the one that held him. You were the one that cried.

In an instant, he was back, mind and soul rejoining body, returning your hug, tight as he could, crying.

The cycle continued as it had before, but you cared this time. You had to.

You cared so much it hurt.

AN: Had this Experimentbro idea in mind for a while. Wrote this a while back because I was getting a root canal. If I have to suffer, so do some skeletons.

No one ever said there couldn't be other experiments inbetween Sans and Papyrus. :)