A merman lounging amidst the swirling waters of a hidden pool!

You concentrate once again on the dark spirals spinning mesmerisingly inside the depths of the seeing stone, itself balanced so perfectly on the pedestal before you. Sudden colour blossoms within the globe, covering its surface with a soft blueish hue that for once banishes the palet of greys and blacks to which you have grown so accustomed. Your vision opens upon a surprisingly well-lit pond lost in an unknown corner of the vast labyrinth, almost entirely surrounded by stalagmites. The pool is large, round and deep, illuminated from below by a powerful, luminescent light that bathes the nearby area in a warm blue glow. Ripples lap idly upon the surface of the liquid, giving the pool an inviting sense of movement and freedom strangely distinct from the foreboding oppression that characterises the majority of this underground prison. You have never seen anything quite like it, although you are not sure if even you have ever explored the innumerable pathways that combine to form the maze of caves and corridors scores of feet below you.

Amidst this welcoming picture, an island of serenity in the typical unwelcoming blackness, you finally discern a creature floating casually on the surface of the water, back arched lazily against a shallow rock formation. In its relaxation, it is so still as to almost blend in with the gently lapping waves, but after a moment you make out a perfectly human body, just about poking out above the surface. The form is not only obviously masculine, but strikingly handsome in appearance. A clean face with glimmering blue eyes emerges, followed by a strong, athletic torso rippling with muscles; not a single blemish is to be found on the skin of this unknown being. Only when you gaze beneath the surface of crystal pool, your eyesight purposefully enhanced by a whispered spell, do you perceive the hidden abnormality of a long, slick, silvery tail trailing off into the depths beneath the creature - a merman, for that is what it undoubtedly is. A vague recollection of capturing this particular specimen, or at least a similar individual, returns from many years ago. You remember the tail as being used primarily for purposes beyond the evident buoyancy it grants. Lust awakes within you anew as you prepare to be transported into this new body.

The possession is surprisingly painless this time, for the merman barely resists your intrusion, content to mentally escape the cove that has been its home for far too long. As such, your adjustment to this new form is brief, quick and comes naturally. You stretch your long, powerful limbs as you would before a bout of exercise, and then flex your tail in order to get used to the new sensation. It is far more elongated that you had imagined, and disappears below for what must easily be several feet. Where naive popular folk tales would place the tail fins, you instead become aware of a large, fleshy protrusion that extends the length of the muscle even further. You withdraw that particular appendage for the moment. It will pop out again when the time is right, there is no need to reveal yourself quite as of yet. The strengths of the merman lie in seduction, not in brute **** or persistence. May as well play the role by the book.

You hear the sounds of footsteps approaching from a distant, as of yet hidden corner, which the welcoming light of your abode cannot penetrate. Who will be your prey this time? You hesitate at first, unsure of what to do, and distracted by your lustful thoughts, but instinct soon takes control. You begin to sing.