A Mermaid

That's when you saw it - a scaly, multicoloured tail, hidden in the water. It was travelling towards you fast, and you still weren't sure what it was.

Taking a look again, you noticed that it seemed to be human, relaxing you now with the knowledge that it wasn't a deadly seamonster.

Just as you close your eyes to relax in the water, you hear a splash on the surface. Opening them to look for the source of the sound, you are confronted by the most beautiful mermaid you had seen, and it was staring up (from the water) at your lactating breasts.