Sans did not sleep. Despite what Doctor Hansen said, he stays awake with Papyrus. The two of them spend hours pouring over the workbooks that Sans has been learning from. The Monster loves to learn new words, and Papyrus is happy to teach him. Pretty soon, there won't be anything left to teach.

Their favorite game is Pictionary, though neither of them know the name for it. One of them will draw a picture while the other has to guess what it is. Sans doesn't recognize anything outside of the lab, but Papyrus explains his drawings when Sans gets stuck. He even writes the word down to show the spelling. Sans's notebook is almost full. They've taken to doodling between the margins in the workbooks.

Doctor Gaster pauses before he unlocks the door to the observation room. He can hear faint voices through the door. He can hear...... laughing. Gaster would later review the audio recordings that monitor the room. It appeared that the artificial Monter was talking to himself for hours. The Doctor would delete these recordings and replace them with the near silent audio of days past.

When Gaster opens the door, Sans can hear it. His magic is humming just below the surface. His giggles cut off abruptly as he spins around to look. Doctor Gaster sees the Monster sitting alone on its bed with the workbooks spread out. He walks over without saying a word. Gaster's creation hunches its shoulders, scared of being in trouble. Doctor Gaster is more interested in where all the workbooks came from. Murphy and Alister were conducting cognitive tests, but Gaster didn't know they let the Monster take books back to the observation room. Gaster's breath halts when he gets a close look at the books. Each has two distinct drawing and handwriting styles. He never tells his coworkers about this observation. He will have to research it in private. There's no time now.

"Come with me, Monster. It's time to work on the attack magic again", Gaster speaks out loud, not bothering to sign.

"Are you mad at me?", Sans asks quietly.

"Mad at you for what?".

"Are you mad at me for using my magic?".

"No. It was expected. I am simply disappointed in the waste of artificial magic", Gaster says, his tone darkening, "But if you ever use attack magic without specific orders, there will be severe punishment. Understand?".

"Yes! I p-promise not to use that", Sans says, stuttering.

Gaster just finds it interesting. Its voice halted even when made of magic. The artificial soul, magic, and copied emotions must be closely linked. Doctor Gaster does not believe that an artificially made being has any real emotion. It's all mimicry. Sans will copy the way he sees others behave, speak, and act. There's nothing real about the body and fake half of its soul. The human half, however, may be worth looking into. The two district handwritings unsettles the Doctor. No scientist before him has put a faded soul back into a body, organic or made of artificial magic. Doctor Gaster decides that he must get Sans alone at a later date to investigate further.

The two of them walk down the hall and to the doors of the gym. If Doctor Gaster had turned around, he would have seen the skeleton hesitate before stepping over the threshold. Its feet make soft, audible clicks on the hardwood floor.

There's someone new standing in the gym, waiting; it's someone that Sans has never seen before. The man is just a little shorter than Gaster, but much more muscular than any of the scientists. Their skin is also much darker than anything the Monster knows.

"Master Sergeant Santos, thank you for coming. This is the skeleton I've been telling you about". Doctor Gaster keeps his tone formal, but it's obvious that the two men have a history.

"I thought he'd be taller", the Sergeant smiles a little, "And please, call me Felix. We both left the army years ago, and you still won't give up those old titles".

"Habits die hard, I suppose", Gaster forces himself to relax. He hasn't seen Felix Santos since they were both stationed together in a foreign country. Gaster was serving as a field doctor before he began more specialized work that led to this project. It's been nearly a century since Monsters were locked in the Underground, and 80 years since the skeleton clan was exterminated, but the military still teaches Monster combat. Sergeant Santos was one of the most skilled instructors that taught the class.

"I have to admit it, but I never thought that I'd be teaching a Monter how to fight. Pictures don't do 'em justice. That thing's just creepy, Gaster". Santos leans his arms on his knees to be more eye level with Sans. He hasn't moved from behind Gaster's legs.

"I just want to warn you that he's very fragile. If it collapses at all, we'll have to stop the training. It's body does not use magic efficiently. I might have to inject it with more", Gaster explains, motioning to another corner of the room. A gurney has been wheeled in with syringes full of artificial magic at the ready.

"I'll be careful. You don't have to worry, Gaster. I've trained enough shrimps to recognize their limits", Santos says, cracking his knuckles. Sans hasn't been able to follow most of the conversation, but he flinches at the sound.

Doctor Gaster steps to the side. Sans tries to step back behind him, but Gaster sighs and shoves him forward, towards Santos. He also pulls the zipper down on San's jacket that way he can see if the soul begins to crack. Gaster is only here to observe and take notes.

"Gaster calls you Sans, right?". Santos feels slightly uncomfortable addressing the Monster directly. He's also surprised at the deep, disembodied voice.

"Yes", Sans replies quietly.

"Ok. I don't know how much you know, but Monsters like you fight differently than Humans. Monsters can attack the soul directly. Once a Monster decides that they want to do harm to a living creature, the battle begins. You have to start the fight first, or I can start attacking you. Your magic should react either way".

The artificial Monster has never had the intention to hurt anyone in his short life. When Sans just stares at Santos, confused, the retired Sergeant makes the first move. He moves fast, closing the distance between them. Sans doesn't react or try to move when Santos lands a punch square to the Monster's chest. Santos didn't hit as hard as he could have, but it's still enough to knock Sans on his ass. Doctor Gaster flinches. He expected the Monster to crumble with the lightest touch.

Sans can practically feel his soul rattle around in his chest when he falls back. There's nothing to cushion his bones when he hits the floor. For the first time, the Monster is scared for his life. Sharp pain jolts through his body. Just like Santos expected, the soul reacts to the threat. Sans's eye lights up as his magic hums brighter and stronger.

The scenery around them shifts until everything is in blakc and white. Sans's coat and bones stand out brightly. Santos clothes have also shifted to white, but his skin is nearly the same shade of black as everything else. What stands out is a bright yellow heart that shows through Santo's chest. When Sans looks down, he sees that his own soul is also glowing in its two bright colors.

"This is a Monster battle". Santos looks around at the color shift. He's never actually fought a Monster before. All his knowledge and techniques have been passed down from when Monsters still lived on the surface.

Sans uses the distraction to stand back up and skitter away from the Sergeant. He's scared of getting hit again, and he's scared of what his magic has done to change the color of everything. He's hating the gym more and more with each visit.

      "Ok, Monster, listen up. I'm only going to explain this once", Santos drops back into a fighting stance, "If you're going into the Underground, you need to be able to fight. With a half human soul like that, you'd stand out even if you weren't the only skeleton. Your survival depends on your ability to kill".