The sign is on the Main Street and points into a quiet side-alley. It reads "Pool", and for disambiguation there's an Olympic-style icon of a swimmer. You don't know this town at all well - most likely you're visiting, business or vacation or whatever - but it seems an odd location for public swimming baths.

You have a look. There's a door at the end of the alley, also marked "Pool", and through it a room and a reception desk. Walls are white with a dark blue horizontal stripe about five feet up. No posters, no leaflets, nothing on the walls except the swimmer logo beside an arrow pointing inwards. Nobody at the desk or in the room, no sounds of people or activity; very quiet for a pool on a hot day. The place feels off, but rather than unsettled you find yourself intrigued. The room's coolness is welcome, anyhow.

The arrow directs you to a hall with the same blue-on-white decor and the same absence of anybody. There are doors to the changing rooms and restrooms. There are also racks of swimsuits: different sizes, styles, genders, lengths, though all of them white with dark blue piping or trimmings. Most inviting, this pool, with costumes provided and no entry charge. Still silence, though broken when a hanger clatters down from the rack. By chance its suit is right for your size, species, gender and preferred style. You have time to kill, you could use a swim, and the oddness of the place calls you in deeper. ("Fly in a pitcher plant", some uneasy part of you might whisper, but if it does then you do not listen.)

You go to a changing cubicle and strip. The swimsuit has no brand label or logo. The cloth feels smooth and cool, maybe some synthetic fabric. At each side of the suit is an odd metal loop, set into a leg cuff or hem. (Go through the racks and you'd find every swimsuit has two such loops.) They remind you of the rings attached to bags and suitcases, there for the clipping-on of detachable handles and straps. The suit's design, with its simple lines and dark-on-white scheme, now seems formal and almost austere: curious impressions to get from a bathing costume. Pulling it on you feel coldly solemn, as if preparing for some lone and lonely rite. The mood lingers: closing your locker on your stuff brings an odd sense of finality, as if saying goodbye to something. (Your stuff will be found afterwards in the alley, which no longer has a "Pool" sign and ends in a blank wall.)

Through a short passage is the pool itself, and your spirits lift again on seeing it. It's grandly large, and you have it entirely to yourself. Completely indoor: no windows, but great white rounded-rectangle lighting panels that are almost sky-bright. The same scheme of cold white with sparse blue lines. You are still alone, no staff or other bathers. The absence of lifeguards is definitely remiss, but you're not here as pool inspector. You dive and splash joyfully, and maybe indulge in the sweet and universally-forbidden cannonball. No smell of chlorine: you guess there must be some modern filtration system.

The far end of the pool is the deepest you have ever been in, and here you find another oddity: a wide round opening in the pool side a couple of feet under the surface. Through it is what appears to be a second pool. There are no doors above the water to this other chamber. Very strange architecture and surely against every pool regulation ever, but your sense of adventure demands you go through. The passage only looks a couple of meters long.

You make it easily through - there are even handholds - and surface into an impossibility. You are gazing down the length of a minimalist cathedral. Huge smooth pillars rise to a distant vaulted ceiling with vast lighting panels; beneath, the pool runs from end to end between tiled floors. The water below you is deeper than ever, the bottom only dimly visible. There are blue bands at the base and top of the pillars, and two-thirds of the way up the great walls; otherwise, everything is again stark white.

None of this makes sense. This structure can't exist within the town; it would be visible from every street. There could be no conceivable reason to build such a thing. Your mind registers these truths, but you find yourself unable to care much; you are too filled with awe, and with an aching urge to swim the great chamber. Halfway along it you realize you have somewhere lost your locker key; you know this will be an issue later, but right now it is a matter belonging to a different life.

At the far end is a second submerged passage: deeper, well over a meter under the surface. You swim down vigorously and again get through with little trouble. The chamber beyond is as grand and huge as the last, though different in detail: the light panels are elongated ovals, and the pool has islands and narrow places that make your course less direct. Another underwater passage, and through it a great round room with a ribbed dome and a great central pillar that together look like the underside of a toadstool. You pause to take in the sight, then swim round the pillar and onward...

And so on and on through chamber after chamber, each different, each vast. Something is granting you stamina: you never tire, never get hungry, though you occasionally take a mouthful of the cool unchlorinated water. The submerged connecting passages are now deep and long enough to be little adventures in themselves, each one a small world of light and shadow through which you pass as capably as a seal. You do not need rest, but you sometimes break your journey to explore a room on foot: climbing stairs, wandering paths and walkways, investigating dim side-chambers. Eventually the water calls you back and onward. Your mind has quietened; sometimes a meditative thought surfaces, more often you move in a peaceful trance. Often you find yourself fingering the metal loops of your costume.

There comes a moment when you know, with utter certainty, that you are doomed. No voice, no message, just sudden unquestionable knowledge. This place is indeed a pitcher plant, and you a fly with no hope of escape. Turn back now, the stamina will desert you and leave you to drown in the first connecting passage. Stay in one room and you will starve. Easier, and certainly more interesting, to continue on to your fate. You are not much troubled by the revelation: returning to the outer world no longer matters to you, and your bones might as well rest here as anywhere. You are even a little flattered: you must be a fly of some value, to merit such a pitcher.

So you continue as before. The devouring entity is patient and does not begrudge you your exploration stops. You understand that the process of digestion has begun, that this journey is preparing your spirit for assimilation. You wonder how your demise will be effected: A great whirlpool, a la Poe? A plastic inflatable kraken? Pool sharks? More likely some gentler process. A pitcher plant does not munch its prey.

You know when you reach the last chamber. As with many others it is round and domed, but for the first time the pool does not reach the end: it stops a short way in, and white tiled floor stretches out all around. There is a separate small pool right in the center, looking not much bigger than a regular house pool, and to reach it you must cross on foot. You climb out by the very mundane and ordinary pool ladder, maybe shake off water if you're canine, then start walking. You stop part-way across and stand, so that the entity can take a good long look at you: it is about to consume you, only fair that it should remember you afterwards.

You walk on up to the central pool. It is about as big as you thought, its shape a simple familiar rectangle, and so deep as to appear black. In the center floats a white pool raft. You let yourself into the water, swim to the raft, sit yourself on it. There are several white pool ropes running from the raft edges down into the depths. Your hand seems drawn to one; you fiddle with it, and the clip attaching it to the raft comes open leaving you holding the end. Without thinking, you clip the rope to one of the loops on your swimsuit: this just feels the right action. To keep symmetry you transfer another rope from the raft to your other swimsuit loop.

The same inner knowledge that told you of your doom now lets you know what you have just done. You feel no horror, if anything, you are a little amused to learn how you have collaborated in your own execution. To test the knowledge you attempt to unclip the ropes from yourself; the clips stay firm. You try to remove the swimsuit; it clings as if it were part of your body. So you are fastened to your doom.

The entity is in no hurry, you feel certain of that. You lie back on the raft and gaze up at the ceiling, into the round bright lighting panel at the dome's center. You relax and are at peace - why shouldn't you be? You've accepted your fate, no point making your last hour miserable with hopeless struggle... Go further. You like being here, being this new person. Your life before was... decent, better than many, but never exactly fun. To swim and wander instead, in comfortable or almost-no clothes, through this vast serene otherworld... so much better. And if this new life has proved a lot shorter... well, everything has is its price. And even the settling of the bill feels like it might not be too terrible an experience.

As if on cue there comes a couple of light tugs at the ropes, warning you to ready yourself. Your executioner is polite. Time to go, then. You slip off the raft, give yourself to the pool. As you float away from the raft you see it pulled under, a preview of your own demise. No doubt it will be reset in the darkness, strange appendages reattaching the ropes.. You quietly tread water, gaze up once more...

Your ropes pull, softly and gently, and the water closes over your face. You are seeing the quivering surface from beneath, watching it draw away... no, watching yourself being drawn down, being taken. You feel cool currents well up around your body. You watch the darkness closing in around the bright rectangle of the surface as you sink. From your lungs you release a single bubble, watch its wobbling ascent, a farewell message to the great room above. You won't need that air soon... you suspect you don't need it even now, that the entity has relieved you of the need for breath and will end you by some means other than drowning.

You are getting colder but the chill is not uncomfortable, and a calm peace is rising as you go down. You may see something drifting across your view now, fur tufts or scales or feathers according your body, and think *Am I already starting to digest, then? It's not hurting.* You gaze and gaze at the darkness and the light, feeling your body calm and your thoughts slow and stop, and at last there is a time when there is light, and darkness, and no you at all.

And after this the little pool has a throat-clearing. Water wells up from its depths, some of it spilling out across the floor around it. They may be scales or feathers or fur: all clean, nothing gross. And it may be that an empty blue-on-white swimsuit, now untethered from its fatal ropes, is brought upwards to turn and turn in the rising current, a bleak salute to its departed wearer, before receding back into the little pool's depths to pass into the entity's recycling system. There will be a new clean suit for the next victim, and the victim after that, and the sign and door will appear in town after town to snare curious visitors not local enough to know that no such place exists there. The world will go on, and the entity will go on, and it may be that in some adjacent dimension you too will in some form go on. Or not. So much about these entities is uncertain. Some day their mysteries will be made clear, as all things will be to our studies, but not yet.