Three

Gaster eyed the live feed carefully.
Everything was normal. Everything was going exactly as his simulations had. He held up the first tests feed next to the current one.
He couldn't fail another monster.
Not again.
He looked up over his desk at the new test subject.
Why did every monster put their absolute trust in him just because he had built the Core? Building something that transformed thermal energy into electrical was easy; and they were willing to give up their Souls over that? Teleportation was an unknown. There wasn't a single solid record for it to happen and monsters were willing to let him use them as subjects for it?
He didn't understand.
"I'm all set, Doctor Gaster." The monster replied, misinterpreting his stare.
He closed his eyes, "Very well. Think about your favorite time on the surface and close your eyes."
The subject did as told and Gaster returned his gaze to the feedback.
He keyed in commands and once again the machine hummed to life. He confirmed that all the reading were normal once again before starting the machine. It glowed, and there was a split second when Gaster read one of the feedback readings changed; he dropped everything frantically keying in commands to the machine; it glowed brighter, but did not stop. Gaster keyed in override commands.
But the machine glowed brighter.
He keyed in another override command, and then another and another and-
Gaster was thrown back from the desk against the wall again.
He regained his breath quicker than the first time, and leapt to the readings again despite feeling his soul feeling slightly heavier.
The same.
He grabbed the first feedback recordings and held it next to the second one. It seemed like the override commands had only slowed the machine slightly as it read the code and calculated outputs.
But it was still a failure.
Doctor Gaster sighed heavily, pulling his chair over to slump down in.
Just as he had, there was a knock on his office door. He didn't even get the chance to answer before it opened anyway, "Heya doc, I'm here to help with that test."
"You're an hour late."
"Well there's so many monsters running around here now that're just dying to hear some of my hilarious jokes and who am I to say no to an audience like that."
Gaster waved a hand away at his assistant, "You're late regardless; the experiment is already over."
"Eager as ever for all that, huh?" Sans walked up next to him, looking at the piece of paper that was still attached to the printer.
"Ill save you the science talk; it was an utter failure. Just like the first one."
"Ouch."
"Yes, 'ouch' indeed." Gaster sneered, turning away from the skeleton to look over at the empty chair.
"I wouldn't call this an utter failure, though."
Gaster immediately turned back to him, "Excuse me?"
"I mean; yeah its not what you wanted. But they didn't just disintegrate."
"Of course they did, Sans! Look at the readings!"
"No, no," Sans turned the paper towards Gaster and pointed at the reading just after the explosion, "When a monster dies, the Soul hangs around for a second, before they turn to dust, right? Here they're just...gone."
For what little it mattered, Sans was right. Gaster still scoffed and rolled his eyes, "Sans that means this is a weapon capable of instantly destroying a monster; my soul still gained a level of violence."
Sans blinked at him, and then the feedback, "Maybe but...this still looks like they're going somewhere."
"Maybe I'm teleporting monsters straight into the lava in hotland." Gaster closed his eyes and rubbed his temple.
"Hey, its not a good something, but its still something."
"Please don't say it like that."
Sans shrugged, putting the paper back on the desk, "Hey why don't you take a break? Papyrus wanted to go to Grillby's after work and it seems like you could use the distraction for a bit."
Gaster ignored the fact that his assistant had only just showed up, but he agreed to go after he wrote his report on the experiment.