Sanscest One-shots (Requests are closed!)

Nightmare x Mermaid!Cross (Fluff)

Requested by my lovely girlfriend Frisk_x_Sans233

---

Nightmare sighed as he walked along the rocky shore, his tentacles swishing from sir to side behind him. It was late in the afternoon, and Nightmare had gone out to watch the sunset, and to distract himself from daily life and clear his head.

He stopped and sat down on a rock, surrounded by some small trees that gave way to the ocean. He looked out into the vast body of water before him, feeling at ease with himself.

Time flew by as he watched the sun set before him, his eyes never leaving the bright colors in the sky as they went from red, to orange, to a soft pink. Before he knew it, evening came on, and darkness quickly followed. Nightmare waited until the last ray of sunlight was gone before getting up and turning round to away.

But, something stopped him. Suddenly, a beautiful voice broke into song, it's harmonic melody filling the air. Nightmare turned to where the sound came from, looking back into the ocean.

Not far from where he stood, there was a small rock poking out from between the waves, and on it there was a pale figure. Nightmare couldn't make out what it was, but he could tell that the source of the music came from it.

Nightmare looked around, trying to find anything that could help him get a closer look. He spotted a boat not far from him, and quickly scurried over to it.

He got in and untied the boat from it's post, and used the oars to push it into the water. He began steadily making his way to the rock, the sound getting louder.

The moon had risen, and with it, Nightmare got a clearer view of what it was under it's light. As he got closer, he could make out the figure was looking away from him.

He stopped the boat once he was close enough and squinted a bit. It looked like a person, but... Wait, did it have a tail attached to it?

Indeed it did. From the waist down, the creature appeared to have a ruby red tail that lightly swished in the water.

Nightmare realized what it was. It was a mermaid! He stared at the beautiful creature before him in awe. Nightmare also realized that it wasn't using words. It's song didn't sound like any language he had ever heard.

The mermaid seemed to feel Nightmare's presence and stopped singing. It turned around, shocked to see Nightmare there. Nightmare stayed still so me didn't scare it away.

The mermaid stared at Nightmare for a moment, it's eyes studying him before it dove into the water, it's tail making a slash when it left.

Nightmare stood in the boat for some time, waiting to see if it would come back. He sighed, seeing it had left for good, and made his way back to shore.

Nightmare came back the next day. He was hoping to be able to catch a glimpse at the creature again. He did the same thing as last time, wait until dark and then take the boat. Like last time, the mermaid came out to sing it's beautiful song.

Nightmare quiet made his way to the spot he had been before and quietly listened the mermaid sing. He listened until the song was done before saying "You have a beautiful voice... "

The siren quickly turned around, seeing him. It was about to jump back into the water before Nightmare said "Wait! Don't be scared, I'm not going to hurt you."

The creature eyed him carefully as it settled back down, but not really trusting him. "I like your singing," he told him. The siren swished it's tail in content, seeming to be happy, but trying to not show it.