(Why? Idk. Also this isn't a ship! I'm not one to ship any form of frans or Chara x sans. It seems wrong to me. Plz don't hate me for that, I don't mind others shipping it. Heck my best friend and cousin ship Frans. It's just that I don't. This'll just show cross struggling, because i'm evil and like to cause suffering to those who don't deserve it >:3
Just for a quick because otherwise it'll be confusing, the song is gonna be like two different pov's crosses and chara's)

Mayday! Mayday!

Cross was alone in his room. It was midnight and he couldn't go to sleep, he didn't want to. If he did chara would take over and kill everyone. He hadn't slept in days and it was taking it's toll on him. He had bags under his eyesockets and just looked as if he could fall asleep at any moment. He was now hugging his knees, rocking back and forth trying to stay awake. It was so hard, he wanted to sleep so badly, it was starting to freak him out. Also chara didn't help, they were trying to get cross to give in and fall asleep. Cross could feel himself getting closer to falling asleep every passing second.

The ship is slowly sinking
They think I'm crazy but they don't know the feeling

No one else knew about his struggles, they just thought he was trying to prove that he was strong and wouldn't give in fast by staying awake for, as far as they knew, almost two weeks. To be honest it was starting to scare them how determent cross was to stay awake for that long.

They're all around me,
Circling like vultures
They wanna break me and wash away my colors
Wash away my colors

Chara had a smirk on their face as they saw how cross started to break down. They were really pushing cross over the edge, it had been long since they had taken over the shared body and today would be the day of their return. Cross was scared, scared of what chara was going to do once they were in control, scared of what was going to happen to him, to everyone else.

Take me high and I'll sing
Oh you make everything okay (okay, okay)
We are one in the same
Oh you take all of the pain away (away, away)
Save me if I become
My demons

Cross was starting to tear up. He never wanted this to happen. He wanted to just live a normal live. He wouldn't be able to hold chara back om his own anymore. Little did he know he wasn't the only one awake that night.

I cannot stop this sickness taking over
It takes control and drags me into nowhere

Cross was gripping at his head, trying to rip chara out of his mind. It was useless. His negative aura had filled the house, waking up a certain goopy skeleton with an unusual dark aura. Nightmare had woken up, feeling power flow into him like water into a bathtub. (Best way to compare shit!) Nightmare got curious as to what had caused him the sudden flood of power and went to check it out, following crosses aura back to the room where cross was.

I need your help, I can't fight this forever

He needed help from someone, anyone. Even if it was just comfort, it would help and he was still unaware of nightmare coming closer and closer. The little ball of determination that was haunting him had noticed the others aura nearing them, but kept quiet about it.

I know you're watching,
I can feel you out there

There he was. Nightmare stopped in front of the room of a now panicking cross that was only tiring himself out more by his own panic. Nightmare was surprised that the innocent little cross could give off such a dark and powerful aura.

Take me high and I'll sing
Oh you make everything okay (okay, okay)
We are one in the same
Oh you take all of the pain away (away, away)
Save me if I become
My demons

Nightmare didn't even bother knocking, his curiousity taking him over. He walked in to see cross panicking on the bed. Nightmare was once again surprised, why was cross is such panic? Did he have a nightmare? No he didn't, nightmare would've known if cross had one. But what could've caused cross to go in this state of panic? Questions roamed through nightmares head as he watched cross panic.

Take me over the walls below
Fly forever
Don't let me go
I need a savior to heal my pain
When I become my worst enemy
The enemy

Nightmare watched as cross started to switch between a grinning chara and a panicking cross. Nightmare snapped out of the sort of trance he was in and ran over to the bed. Yes, the aura was good for nightmare, but somehow he felt worried about cross. Nightmare grabbed the switching pair by the shoulders and looked at them. They started to talk, one voice soft as if they had been crying for a long time and hadn't used their voice for god knows how long, it was cross.

"Take me high and I'll sing
you make everything okay"

Cross said, the voice switched to another one, it sounded more confident, but was also soft. The figure that was now sitting in front of nightmare wasn't cross, nor the abomination of the two glitching. It was clear as day that the grinning figure in front of nightmare was chara.

"We are one in the same
you take all of the pain away"

The glitching started again as chara stopped talking. Cross had tears streaming down his face and chara had an insane grin stuck to their face. It looked weird seeing the two emotions switch between each other, a sight nightmare never thought of seeing.

Take me high and I'll sing
Oh you make everything okay (okay, okay)
We are one in the same
Oh you take all of the pain away (away, away)
Save me if I become
My demons

Nightmare couldn't do anything as the glitching started calming down and more and more of chara started showing up as crosses appearance started to become less and after a while stopped. The only once there are Nightmare and chara. Chara took out their knive and the two of them got ready for a fight that would last until oy one of them remained. Cross was now flying around as the ghost chara once was, pleading for them to stop and give control back. Chara had other plans and they started a fight with nightmare.

Take me high and I'll sing
Oh you make everything okay (okay, okay)

Nightmare got to dodge the first few attacks, just like chara.

We are one in the same
Oh you take all of the pain away (away, away)

Nightmare wouldn't be able to fight forever, he was starting to slow down as the battle proceeded and surely...he got hit in the soul, falling to his knees and he started to dust. Chara looking at him with the same grin, they walked out, leaving night are to die. Cross stayed at nightmares side till the final breath. He might have been gone from view, but he still had his aura, it was weaker, but nightmare could feel it. Nightmare gave a small smile. "Hey cross, go get some sleep will ya?" He asked, surprising cross. Cross nodded sadly and said: "Yes, I will." Even though he knew nightmare couldn't hear him.

Save me if I become
My demons

Nightmare colapsed, his dust spreading on the floor. Cross cried as he was forced to follow chara and watch them kill off everyone in the house. First nightmare, than killer, dust, horror...chara went out, not satisfied with their deaths. They went to the village on the light side of this world and started to kill there. Toriel, Grilby, muffet, undyne, monster kid, asgore...until they finally got to a simple little house that looked different from the rest. Cross knew the house, instantly trying to keep chara from killing the owner. If they would, all emotion would be lost. Chara ignore him and walked into the house, oh how the owner was so stupid to leave their door unlocked at night. Chara went through the house in silence, coming up to the bedroom. There he was, the small skeleton, dressed in mostly yellow, was laying on the bed, sleeping peacefully. Chara walked up to him and with a simple slash send them to their death. 'Heh never thought dust could resemble glitter this much...' chara thought to themselfs. 'Oh well, DREAM had always been a weird guy.' They thought as they left the empty au behind and went on to the next.

(Oh how I love a happy end, don't you? :3 man I should stop writing this late, it just gets out more feels.
See ya, Lisa)