AU Undertale one-shots

Undersail! Sans x Mermaid! Reader

You smoothly moved through the water, your tail flicking swiftly as you fallowed the same ship you have been for a month. You would ecationally jump out of the water for a split moment, like a dolphin, to glance at the monsters on the ship. You kept a distance thoughh because you had heard rumors that some pirates capture and ether sell or kill mermaids.

You heard one of the monsters shout something and a rope flew down from the ship. This would normally happen so they could catch fish for dinner but you happened to be in the way at the time. You tried to avoid it but your tail got caught on the inside of the net. You struggled but it made it worse. A few fish soon suffered the same fate. The net the tugged upward. You had soon reached the suface of the water. 

Your tail began to fade now that you were out of the water and on deck. "U..uh S..Sans!" You heard a monster say. You couldn't see much through the net and other fish. "What is it...o..oh." You heard this 'Sans' say. "A..Alphys, go g..get her something t..to wear." Sans said. 'Alphys' nodded and began to untangle you. You did, however, still have on a chest wrap you made from some cloth you found in a sunken ship.

Alphys was holding a blanket and gave it to you. You wrapped it around yourself and looked at her. She was a short yellow lizard. "C..come, on. I..I'll get y..you s..something b..better to wear." She says. You try to stand but fell. "L..let me h..help you." Alphys says. You lean on her shoulder as she elped you into a small room. You sat on the bed and she gave you some tan pants and a dull (f/c) shirt. "Whats y..your n..name." Alphys asked. "(Y/n)." You say. "H..how d..did you e..end up l..like, um, that?" She asked looking away a bit. 

"W..well, ok, p..please d..dont tell anyone, y..you seem trustable. I..I'm a mermaid, m..my tail disappears when I'm o..out of the w..water." You say. "W..wow! Thats s..so cool!" Alphys says. "O..oh, I'll be r..right back." She says and leaves the room. You sit there looking at the room. A sudden nock on the door was heard.

You said nothing. The door then opened revealing a short skeleton. Your eye widened in shock and you backed away a bit. "Hey now, not need to be so chilled to the bone." The skeleton said. You held in a laugh at the joke but it slipped a little. "Heh, my names Sans, Sans the skeleton." He said. So this was Sans. "(Y/n)." You reply. "Now, I know a normal human couldn't survive being in the ocean like, uh, you were." Sans said. You grew nervous again. "And I happen to know that your a mermaid." That last sentance made you freeze. 

Sans saw the fear on your face. "Hey, I'm not gonna hurt'cha. Those blasted rumors about the whole killin' and sellin' ain't true with us." A wash of relief came over you. "I, uh, I've seen ya swimmin' around the ship a lot. Heh your very beautiful in the water." Sans said, a blue blush on his face. You blush as well and mutter a 'thank you'. Just then, Alphys came back. "S..sans! I d..din't know you w..were in here." She said. "Oh sorry, I'll leave." He said. 

--------time skip---------

It became night and you stood at the edge of the front deck looking out at the stars. "You aren't thinkin' of jumpping back in when we've only just met, now are you?" A voice said from behind her. She turned to see Sans. "Oh uh, no, just looking at the stars." 

U.Sl!Sans P.O.V 

I saw (y/n) on the deck. She was leaning against the railing and looking out at the stars. Her silky (h/c) hair swayed gently in the ocean breeze. The starlight making her seem to sparkle. I walked over to her. "You aren't thinkin' of jumpping back in when we've only just met, now are you?" I say and she jumps a bit, startled. "Oh uh, no, just looking at the stars." She says. Her voice was so beautiful, I wish I could hear her sing. 

"Although, I can only stay above water for a maximum of a week." She says looking down. "W..what happens then?" I ask. "I will become really sick then possibly, um, die." She says. My heart sank. "Oh." Was all I managed to say. "Well, I suppose while your here we could get not know eachother." I say blushing a bit. "Sure!" She replies giving a stunning smile. 

---------another timeskip---------

The ship had docked for more supplies. You had slipped back into the water. Sans sat at on the docks edge looking down into the water and sighed. You looked at Sans from afar. You had grown to love the punny skeleton. If a final moment of decision you dove under water and swam towards him. 

As soon as you were close enough you popped out of the water and kissed him quickly, then fell back in the water. Sans had a blue hue on his face. You poked your head from the water. "U..uhm, s..sorry." You muttered. Sans look of shock turned into a happy one. He bent down and kissed you. His was longer, and sweet. He pulled away. "I love you (y/n)." He said. "I love you to Sans!" You say happily. "Though I'm not sure how it's going to work." You say a bit doubtfully. Sans chuckled and kissed your fourhead. "Well find a way." He said.

From then on you both did find a way and were able to live together. 

A/n: very sorry if this one sucked! I tried to come up with an idea for it but I'm not sure how it turned out. X3