100 and One

Despite its seemingly indestructible nature, #100 was only considered a prototype simply because a secret government science facility has no use for an immortal being that won't do what they tell it to.  They kept him around because they couldn't exactly get rid of him, but they couldn't let him go either (these experiments aren't exactly ethical, or... legal.) So, #100 stayed at Black Mesa and continued living there, spending most of his time slithering through the facility's ventilation system.
One day, xe dripped through the cracks of a vent that just so happened to be situated above a strange room. Or rather, the room was somewhat normal, but its contents... There, he met many of the same man - supposedly. They acted similarly, yes, and they all looked near-identical; but one man in particular piqued xyr interest. The thing that surprised #100 about this man was that he was the only one to actually address xem.

Amongst the chattering clones, #100 and the man introduced themselves; #100 with its number, and the man with "Doctor Coomer." Of course, the Doctor had said, they were all "Doctor Coomer", but he hadn't a separate name for himself. Not just yet.
The pair met up frequently after their introduction, and soon become closer knit than wool. They decided that they ought to have names to define them from each of their many counterparts; the Doctor took to calling #100 "Goopy", "Gooby", or simply "Goop"; and #100 decided that the Doctor should be called "Doctor Cotton", on account of his fluffy white hair. The two got on famously, a pair of instances that should not have been, and yet they were. Unfortunately, all good things must come to an end.

Dr. Cotton was careless. He let his presence be known as an individual, and it caught up with him. He was quickly disposed of at the hands of a security guard. Good things must come to an end, but this was a fact Gooby did not want to face. In an act of desperation, once the coast was clear, ae did something ae would soon come to regret: Gooby absorbed the Doctor. Wrapping its melting, dripping form around his rapidly cooling body, it encased him. It thought that, just maybe, there was a chance it could bring him back. Force a sliver of life back into him, reignite his soul and bring back the life to his eyes. But nothing happened. For weeks xe waited, waited for something to change. Any signs of life. But none came. Eventually, Gooby accepted that he couldn't hold on to his friend any longer. At least, not all of him. 

Over the next few years, the Doctor's remains stayed suspended in the slime of Gooby's body. At first, they were painfully visible. The reds and greys and browns were all so sickening. So, Gooby covered them up with one of the Doctor's T-shirts. Eventually, upon lifting the shirt for the first time in a while, ae discovered that the remains were no longer visible. Ae panicked, fearing that they had dissolved completely. After all, ae had been squeezing and dripping through tiny crevices as much as ae had always used to. 

Ae came to the conclusion that perhaps that was for the best. The Doctor was gone, and it was time for xem to let go. Unbeknownst to xem, however, the years-old organs had bonded and combined with the goop of xyr body and nestled themselves in to xyr very core. When in a fully-liquid state or in aer normal form, the organs were completely invisible - but they were there , capable of changing states and viscosity like the rest of Goop's body. 

It hadn't completely let go. Even the simple thought of losing Doctor Cotton filled Gooby with terror, and this carried onto its physical form.  It wanted to let go, but it was afraid; so its body didn't let it.