Slowly.

Despite knowing you are a good swimmer, you seem to be going slower than usual. You start treading water, wondering why but unable to think of anything substantial you continue out towards the middle of the pond.

The cool thick water of the pond reminds you of its presence, chilling you a little, but you can also feel your body warm up to counteract the coolness. You continue swimming, despite it being slow you are making steady progress.

Each stroke seems to be infinitely subtly different than the last. It's only after another ten strokes does the feeling become something significant.

I can't feel the water around me any more...

Wondering what's going on you again stop your progress and raise a hand out of the water... and are struck rigid with fear.

My hand... my arm... it's black!

Looking closer you see that not only has your skin turned a midnight black but there also seems to be a thin coating over it, like

The water.. has congealed around me?

You quickly swap hands, raising the other out of the liquid and notice that it too is a very black colour now.

A quick thrust of your legs and feet (and a quick jerk of your inappropriately timed hard cock) tells you that your arms may not be the only limbs now covered in the quickly hardening stuff.

Panic rising, you swim harder than ever towards the far bank and reach it easily enough before quickly pulling yourself out of the water.

You sit down on the bank and recover from your hard swimming efforts, taking a moment before lifting both your hands up to inspect what's happened. The "water" has definitely caused this you think.

It must have happened when i felt cold and kept my body warm..

You take a few minutes to run through a few cooling and heating spells you know to try and either melt it off or something but it seems content to stay as it is, even solidifying even more. You wrap a hand around your wrist and attempt to wipe the stuff off.

That seems to work a little bit, you can dislodge some of it but you can't separate it off of your hand, then your grip slips. You watch in fascination as the stuff quickly moves back over your wrist of its own accord and seals you up seamlessly.