Toriel looked at Sans with a calm expression as he had finished talking. Toriel was still skeptical at the way sans explained his actions when he pointed out he may have been overprotective, but that wasn't enough to say he was in love with Papyrus.

"Are you sure it was love and not just you being a good brother?" she asked.

However, Sans looked down at his skeleton hands and sighed.

"Nope. You see, it got worse when..." Sans trailed off. He seemed lost in thought, but then he started to shake, which caused his bones to shutter and rattle.

Then, sans spoke in a low and dangerous tone.

"When Mettaton started flirting with my brother..."

Oh yes, he remembered it clearly, every time Mettaton interacted with his brother he would hit on him relentlessly, regardless if Sans was in the room or not.

The pricks of light vanished from Sans's eye sockets. His expression was dead-serious. Even his smile seemed to have become grimmer.

'So this is what sans looks like when he's angry.'

However, her thoughts are cut short as Sans spoke up.

"I swear to god, I mean. He flirts with everyone! and he always flirts with my brother when I'm within earshot!"

"O-ok sans, but please calm down," she said softly.

Sans continued from where he left off.

...

Many things would go through his mind whenever Mettaton would interact with Papyrus.

'You're too overprotective.'

That phrase would resurface and continually echo from within the depths of his mind, and it was the most re-occurring thought when he tries to calm down.

Other thoughts would get mixed in as well.

'He's old enough to date whoever he wants.'

'Leave him be.'

'you'll get in the way.'

'Look...see? they're better without you.'

'He's fine.'

'you're fine with this.'

However, these thoughts alone did so little to rid of his anger...was that what it was?

He so badly just wanted to rip each of the robot's limbs off, starting with his legs, and he was about to do just that as he raised his hand toward that robot slut.

but, as he was about to use his magic, laughter could be heard, snapping Sans out of his deadly trance

"NYEH HEH HEH!"

It was then that Sans looked up and noticed that Papyrus was smiling, it sunk in, and not in a positive way.

Sans hesitated as his eyes trailed his extended arm toward them, Neither didn't even notice

'But I couldn't...he was a part of his happiness, I couldn't do that to Papyrus.'

His arm became motionless and fell to his side.

'I can't take away his happiness...'

Just like that, he had to let it slide.

...

Toriel could tell by the way he explained it, that Sans held an extreme amount of resentment toward Mettaton. Here Sans was laying his head down on the table as he went into detail about how Papyrus would always watch Mettaton's shows in admiration, and despite not liking how Mettaton gets his brother's attention, he made him happy.

Sans still held hollow and dangerous expression.

his voice still dripping with resentment and depression as he spoke: "Oh Toriel, you should have seen the look on his face when he came home the same day and said-"

...

San's POV

I was in the kitchen, still feeling bitter about Mettaton's interactions with Papyrus. They were able to go to a concert thanks to Alphys, and ever since Pap spoke to Mettaton face to face, they became close, maybe too close for my liking.

I thought about going to Grillby's to cool off, but I wasn't feeling like teleporting anymore today.

I reached into the refrigerator in search of a ketchup bottle, and it was at that moment when Papyrus came into the kitchen.

"I, THE GREAT PAPYRUS, GOT A DATE WITH METTATON!" Papyrus announced

"WHAT!?" I screeched, the light from my eye sockets vanished from the shock, I turned around and saw my brother's eyes shine with pure excitement and a blushing red face.

The moment I saw his face, it was nothing but innocent admiration and joy.

It ticked me off, and I could feel that deep pitch blackness making itself comfortable within my rib cage.

Papyrus seemed to notice that I became silent, but took it the wrong way.

"SPEECHLESS? I CAN HARDLY BELIEVE IT MYSELF!" Papyrus said, he honestly looked like an excited child. Papyrus kept rambling on, having one gloved hand in a fist and the other to his hip, as he expressed his so-called tactics for his date proudly and with confidence.

"AND KNOWING METTATON HE'S PROBABLY HAS EXPERIENCE WHEN IT COMES TO DATING! BUT I, THE GREAT PAPYRUS, CAN OVERCOME ANY ADVANTAGE!"

I walked passed Papyrus without looking him in the eye and left the kitchen. I took a few steps into the living room just to get out of the kitchen to get some distance as Papyrus kept the conversation going.

"I MEAN, I HAVE BEEN ON A DATE BEFORE SO I KNOW WHAT I'LL BE UP AGAINST!"

I dared a glance over my shoulder. Papyrus was still in the kitchen with his back turned to me. My left eye flashed cyan.

"BUT I MUST CONSULT THE DATING BOOK JUST TO BE SURE. NOBODY CAN BE TOO PREPARED!" I could still feel his smile radiate like the sun.

All I could say in the same dull monotone voice was:

"good for you bro, you'll be so popular."

"YOU-YOU THINK I'LL BE POPULAR SANS?!"

"..."

"SANS?!"

"..."

"SANS?"

However, the moment Papyrus turned around, I was already gone.

I had teleported to my room.

It had caught me off balance, so it caused me to fall backward. My back collided the door, and not having the will to hold myself up much longer, I slid down to the floor, my legs spread out. The only way to describe it was that I was in a daze.

the cracking sound from within my skull became more noticeable and louder 'seriously what is that sound?'

All these voices in my head become mixed noise.

My vision was becoming consumed by this dark hazy shade. The same tight and suffocating feeling was even harsher, and It took me a bit to notice I was suffering something similar to a panic attack.

I held my hands up in front of me and tried to focus on them. The voices slowly became less mixed, until eventually, they became more and more comprehensibly clear.

'Calm down, alright? You're ok with this, remember?'

'He can date anyone he wants.'

'he'll make him happy.'

However, other voices became more prominent or noticeable than the others, and they came in hushed whispers and were darker.

'He's dating Papyrus, that bucket of bolts slut is dating your brother!'

'Papyrus is not yours.'

'You're so selfish!'

One particularly dark one arose from the rest, and it struck my entire being, and with what little movement I was shivering, absolutely petrified.

'He'll leave you.'

That particular thought outweighed the others, and it was consuming, restricting, and overwhelmingly suffocating. It almost destroyed me, the mere thought of it.

It was already bad enough by suffering insomnia and post-traumatic stress disorder.

I covered my face trying to pace myself, but this was overwhelming. I tried to regain control over my thoughts and focused only on the hum of my soul.

"Why..." my voice came out in a desperately broken sob.

"Why can't I be happy for you?" I whisper in frustrated agony.

'I should be happy for him, right?'

'I feel like the worst, what is wrong with me? why do I feel like this?'

Suddenly, all those voices finally stopped.

I removed the hands from my face and bore an intense expression, one that held a lot of anger. Probably just as much as when the kid had killed Papyrus in a different timeline. Hell, I didn't notice how my left eye was glowing between cyan and gold while the other remained hollow. However, that hardly matters.

"THAT BASTARD DOESN'T DESERVE HIM!" I declared with a very low growl. 

I had made my resolve 'I can't lose my brother to HIM!'