Gaster was an idiot. He should have seen it sooner.
They weren't just experiments anymore. He didn't know if they were ever just experiments. They could feel pain. At least, the smaller one could.
He had been doing the tests, pushing the not-doll around, and had accidentally dropped it (him?). And the thing (boy?) had softly said ow.
That one word had Gaster rushing around the room, shutting off the equipment and scooping the doll (boy?) off the floor. He walked to the room he stored the dolls(kids?) in, dazed. Were the dolls(boys?) Sentient? Was that even possible? Granted, he had used parts of his soul to help give them shape, but they were just dolls(Boys? Boys.) he had created out of human remains.
A dead human body had fallen into the Underground, and Gaster had taken it as an opportunity to learn more about humans. Melt it with his magic, turn it into two separate lumps, and blam! The flesh had never reformed, but he managed to get them to hold the shape of two skeletons by mixing a slight bit of his soul into the lumps. He thought that they took the shape of a skeleton because the flesh of the original host was unable to persist after death. Now he was wondering if it was because of his own soul.
He knelt in front of the second child, putting the first down more gentle than he ever had.
"You guys can feel pain. I didn't know that. I need to know if you can think, too. Can you understand me?" He asked the children, not really expecting a response. They had never shown any signs of life before, so why would they now?
One of the children looked up into the eyes of Gaster and nodded.
The child wondered why the monster suddenly seemed sad. He didn't understand he wanted to understand he felt this was important. He was also so tired thinking was hard and the monster had done lots of things with him earlier some them had hurt and he wanted to sleep with his brother like he usually did after the monster did things.
Gaster rocked back on his heels, falling gracelessly onto his rear. They could think. They. Could. Think.
Tears came to his eyes. What had he done? He should have seen it sooner. How they were in different forms when he came in the morning. He thought that he was just confused, that he must have shifted them before he went to bed. And when he made them shift... Did it hurt them? He had just reached into their magic and pulled until they changed. And Angel Above, what had he done?
He suddenly felt dread. Did they have souls? And if they did, what did that mean for his? He reached out, grabbing with his magic. Ping! And out of the smaller one's chest came his soul. A full monster soul.
HE SCREAMED, he had enough pain that day and just wanted to sleep
Gaster reeled in shock, at the scream, at the soul, and what about his, and he pulled at his own chest, at the same time pushing the smaller ones soul back. His soul came out, at it was wrong ot was so wrong. There was a whole in it and it felt so wrong and what happened, and what about the other-
He started to pull away he need to get away and he shifted into a canine and started to pull his brother with him trying to escape before there was more pain and collapsed on the floor unconscious.
Gaster backed away in horror, and in respect of the want to get away. He turned, walking out of the room, planning to at least get the boys some bedding now that he knew that they could think, could feel. He left the door open, not wanting to trap them, to do them more wrong. He had messed up so bad, and how long were they able to feel? Just how much had he put them through?
The larger one of the two children was suddenly alone for the first time ever he was scared he cried out trying to wake his brother and shifting he howled and headbuted the older child. He was slowly getting sleeping and he decided to lie down with his brother and falling asleep he hoped the monster would still bring them food.