"Your broken eye does me no more good than it does you, you know. It's very inconvenient."

1S grabbed the sides of the chair, glaring at its creator with his one good eye.

"inconvenient-"

The doctor continued, paying no heed to the test subject's outburst.

"Physical damage is one thing, but impaired eyeglowing opens up a whole new host of potential emotional problems to deal with." He tilted his head slightly and looked at the smaller skeleton's functional eye. "...And, as you've probably gathered, emotions aren't my strong suit."

1S was taken aback.

"...did... you just make a joke?"

Gaster smiled at 1S's bewilderment, amused by how surprised it was. Did it really think he didn't have a sense of humour?

He finished calibrating the matix and turned it on.

"Now stay still and try to relax. It should be relatively painless at this intensity. Then as time goes on-"

The machine surged as 1S' skull exploded in a burst of magic and bone, knocking the older skeleton onto the floor. He stared at Sans, sockets wide as the edges around the explosion began to turn to dust.

"No, no NO!" he shouted, getting up and placing his hands on the skeleton. He poured every ounce of healing magic he could muster. It wasn't enough. He was dying. He was dying. Dust was spreading. He couldn't save him. His soul thrummed. His eye flashed a multitude of colours, frenzied, panicked.

"This wasn't supposed to happen." He wrapped his arms around the dying child, instinctively drawing him closer to his soul, and squeezed his eyesockets shut. For that moment, in the silence of the lab, with only the faint hum of powered machines, it felt as if they were the only monsters in the entire underground. He failed them. "I'm sorry..."

Why was he doing this? He knew he lost his ability to... heal...

The skeleton squirmed in his grasp. He let go and looked down at it.

No.

This couldn't-

It stared up at him, seemingly as surprised as he.

How-?

It can't-

He looked at the test subject as if it had just stabbed him in the chest.

"wha..."

Gaster ran out of the room and locked the door behind him.

He clenched the doorknob, distraught. He thought he'd put this behind him. That the two skeletons were things, not monsters. Tools to be used for the good of monsterkind. The keys to breaking the barrier. Meant to be useful, and nothing more. His creations. Nothing more than useful, valuable possessions.

And yet as Dr. W.D. Gaster tried to convince himself that the skeletons that he had marked and labeled as his belongings and refused to care about meant nothing more to him than his laboratory equipment, it felt wrong to him.

He knew what it took to heal someone. A strong constitution was important, but as with all magic, for monsters, at least, nothing can be done without intent. A genuine desire to help, care for, tend to someone was central. And he didn't care about the test subjects. They were only things to him. Important and valuable things, but simply valuing a thing wouldn't allow one to mend it.

But, for that moment, 1S was...

No. It was nothing more than a fluke. A lapse in judgement brought upon by the suddenness of the explosion. He would remain objective.

He steadied himself, straightening his posture and opening the door. He focused on what he needed to do.

He had to stay determined.