UnderGuile

Undyne's Last Words

A couple hours later, Sans awoke on his couch with Papyrus worried.
"BROTHER! YOU'RE FINALLY AWAKE! WHAT HAPPENED?" He asked. The memory of the fusion played inside of Sans's skull. He knew the fusion did something to him, but what? Sans's changed his expression to a lazy one.
"Eh, I probably just lacked sleep and passed out." He casually told his younger brother.
" Well, you did surprisingly stay up really late, as Undyne told me." Papyrus says in a rather calm tone," Why did Undyne wanted to see you?" Sans remembered when Undyne wanted to see if he can actually fight for once; she was BONE tired afterwards.
" Well, Paps, for some reason she wanted to see how strong I was, weird." He explained.
Papyrus gleamed and stood from where he was knelting down, giving Sans space to wake up. Sans sits up. Three knocks on the door left Sans tense. 'What if it's them?' He asked in his head. Papyrus hurried to the door and opened; it was only Undyne. Sans's tense is replaced with relief.
"Sans! C'mon one more time! I know this time I'll win!" Undyne challenges. Sans sighs.
"One more time... then it's back to Papyrus's training." He replies.
"CAN I WATCH!?" Papyrus asks excitedly. Undyne laughs and nods.
" Yeah, it will be better for your training."
And with that, the three of them go towards the Waterfall. One of the best fighting places is there. Sans and Undyne starts simply fighting. Something; a feeling, makes Sans stop in his tracks, doubled over. He's breathing heavily and starts to feel as if he's looking control, but that's impossible. His left eye starts to flicker, but not blue... green and red... just like the fusion's eyes! Is this what they did to him? Took control over him?
Sans tried fighting for control. No use. He's gone. Sans could only watch. 'Sans' looked at Undyne with a crooked smile. Undyne jumped back a bit. Papyrus with a worried look.
"Sans, are you okay?" Undyne worriedly asks. 'Sans' only laughs with his left eye flaring in green and red flames. He did an attack that Undyne barely dodged from.
"Your eye is a different color than blue. What's up with you?" Undyne asks dodging more of his dangerous attacks. 'Sans' acts like he was back in control; to trick her. Sans couldn't do anything but to watch helplessly.
"Sorry... just, ya know... warming up." He replies. Undyne's tenseness disappeares. 'Sans' strikes Undyne unexpectedly with a bone attack through her chest. Right then before Undyne was turning to dust, she tried to attack him with a spear. It hit Sans's left side of his skull, which is now in a bunch of small cracks.
"P-please don't let m-me d-die!" She cries. Papyrus runs to Undyne. 'Sans' uses his telekinesis to throw Papyrus away from Undyne. She faded completely to a pile of dust. Sans was back in control. His left pupil is now different from the right one; a blue circle. Sans's vision blurred and he, once again, passed out.