With the youngest happy we made our way inside. I offered to make dinner but Papyrus mentioned Gaster leaving leftovers in the fridge. It was some sort of salad, I wasn't listening. All I knew was it didn't need to be heated up so I could leave him to get some for himself.

I got back upstairs and into Sans's and Papyrus's room. The older skeleton was shaking as my dad had finished telling him something. Any checkups they'd done were finished. I waved when Sans glanced my way but flinched as he quickly averted it. "So? Dad?"

Flinter smiled weakly. "He should be okay as far as I can tell. His soul is weak, but the change is close to completing. As long as he takes it easy then the change shouldn't be a problem. As for that blaster… he needs someone to teach him how to use it."

"But Grilbz-" he paused. "Grillby has been teaching me," Sans muttered, almost whining. Like he had been telling my dad that.

He ignored the statement. "The blaster is dangerous. If it's an emotion based attack then the change can affect that. The light blue your soul is changing represents two emotions: fear and anger. It can also mean joy and bravery. Depending on how you react to the change your soul can become a compilation of these emotions." Flinter gave a reassuring smile.

Sans was still uncomfortable.

I crossed the room and joined them on his bed, sitting beside the skele. "Now that he's explained it to you, do you understand why I told him?"

It took him a moment… but he finally nodded, still not looking at me.

"I may not know you, Sans, but I care."

"You get paid to watch us," he huffed.

I sighed. "I watched you and your brother thinking I was just… helping out. I didn't expect Gaster to pay me for it. I already decided I'd watch you two even if he didn't pay me."

The child's right eye gave a faint yellow glow, more than half the circle gone. "Really?"

My smile was genuine. "Really."

His eye flickered but continued to glow before he finally smiled, bright. "You really mean it?"

I had to laugh. "What more do you want from me? You've grown on me. You and your brother." I couldn't help but pat his head roughly, being careful not to hurt him. "Now, Papyrus is downstairs eating. You hungry?"

The lights in his eyes turned white again and his smile didn't fall. "Yeah."

Things felt back to normal after that. My dad stayed with us and munched on a snack he'd brought. I stole a few from him while Sans distracted him with some pretty bad salad puns, "LETTUCE be thankful that-" and I wasn't paying attention to the rest as I saw Papyrus nearly choke from rage. Things were back to being fun like they used to be.

I had thought of making something else for them to eat, but Gaster had made sure the 'salad' was more than just lettuce and croutons. It was a strange concoction of… well I didn't even know. If Papyrus hadn't of even called it a salad in the first place I'd of thought it was something else entirely.

"I should ask this salad to shop for me," Sans finally said when I'd zoned back in.

"Why's that?"

"Cause it's so good at DRESSING itself!"

My dad and I didn't expect the suddenly joke and had to collect ourselves after that. It took just that long for Pap to calm down as well. I liked knowing that things were back to how they were. It wasn't until we were on the couch telling stories that I realized how much time had passed.

The front door opened and Gaster stepped in, just as tired looking as ever. He stopped, seeing my father.

"Dr. Gaster!" Flinter announced and stood to greet him. "It's been too long. You look just as worn out as I remember."

Recognition sparked in his eyes. "Flinter? We never see you at the lab anymore. How've you been?" It was the first time I'd seen some sort of emotion on him. The skeleton seemed almost immediately to relax as he reached out to shake my father's hand.

"Good, good. I've been running the bar in town. Keeps me busy. If you ever need a hand over there, just let me know."

"I'll send you a smoke signal."

The two shared a laugh over it. So, Gaster was a jokester too. Guess my dad picked it up from him. Sans was too much of a natural for his puns to come from me mentioning just one.

"Sorry I didn't tell you I'd be here. My son wanted me to meet the boys. He loves watching them."

Gaster glanced our way with a soft smile. A dad's smile. But then he blinked and the smile fell. "Sans?"

I couldn't help it and followed his stare. The smaller skeleton's eyes were wide and that blue glint was sparking up. It was obvious something was wrong. Of course I knew it was fear. My dad knew Sans's secret and we'd never told him if we'd tell his dad. I jumped right in without thinking, "Sans broke the light in his bedroom earlier. We were messing around and things got a little out of hand. I didn't know where the light bulbs were and I said we'd ask when you got home." When Sans turned to me, confused, I added, "He didn't want to get in trouble for it. It was just an accident."

The monster scoffed, coming over to pat his son's head. "It's just a lightbulb. You think I'd care? Now, break a window and maybe you'll get grounded." That smile was back, light and loving. "Don't worry about replacing it," he said to me. "I'll do that."

"If you don't forget," Flinter remarked making Gaster flinch.

I loved seeing a new side to him. Gaster always looked so tired, I had thought he only worked and slept… if he even slept. Knowing he could pull a 180 and have the face of a father made me feel relief. Not that I thought he was a bad father, but with Sans's fear of him it had had me worried.

When the taller skele and elemental left the room, poking fun at each other about 'how many monsters does it take to replace a lightbulb', I looked back to Sans and gave a wink. He hesitated before his yellow eye flared into a faint ring and he smiled. "Thanks."

"I told you. I just wanted to make sure you were alright," I whispered so Papyrus didn't hear. Who had been surprisingly quiet this whole- "And he's asleep." The smallest skeleton was curled up at my side, grip on my shirt loose as he snoozed. I scooped him up in my arms. "I'm going to put your brother to bed."

Sans nodded. "Um… Grillbz?"

"Yeah?"

"I- uh… Sorry. About earlier? I just… Ah don't know. Ah thought that… I mean- this is a huge secret an' junk an' ah just felt like-"

"It's okay. I get it." I grinned. "If it were me, I'd of gotten upset too. But you're one of my friends now, so I want you to understand that anything I do or say is never meant to get you in trouble. I kinda knew that if things weren't going well that you weren't going to tell anyone anyway so I just wanted to make sure."

A moment of quiet… and Sans nodded. "Thanks."

5ive here!

I wanted to say thank you for reading this so far ^^

UnderSitter started out as a story I would write on my phone's notes that I'd said to my friend Quad.

It came from the idea that we LOVED thinking of Gaster as a super forgetful parent because he was always so tired from work.

Originally it was going to be in Sans's POV, but as I began writing I realized that it needed to be from Gillby's in order to get the story moving along and truthfully... for a character that I know nothing about his CHARACTER, I love writing for him. I've been able to make him my own while still seemingly being who he originally was.

Helps to have so many cute comics out there for him :3

Anyway! Updates will be slowing down since I've only written up to Chapter 10. I've gotten the next one started and as soon as I finish it I'll be posting it.

After this chapter, all other chapters will be posted as soon as finished! I tend to go into moods of "I MUST WRITE" and I'll easily get 1 or 2 chapters out a day. Let's hope that happens soon!

Love you guys! Don't forget to comment, follow, and share!