Skye's been noticably hungrier than usual, and it all comes to a head on this particular day: his stomach is practically growling at even the thought of food, no matter how much he eats. Eating is rather difficult, though, because as time goes on, his gums become increasingly sore, making eating nigh impossible right before his changes.
At first, the changes might not even be noticable, the skin of his arms darkening and turning into a sandpapery texture. However, it is rather noticable when his fins begin to grow, and even more noticable (and painful) as his fingers begin to fuse, still clearly in sets of two but impossible to separate anymore. His gums begin to bleed as another set of teeth grow in under the first, starting the process of the continual replacement of his teeth. A third row comes in just as painfully as the first, coupled with the stretching of his ears into fin-like structures. However, where the pain has ended up top, there is plenty more to go below.
The bones in Skye's feet begin to pop as they warp further into fins, the ankle protrusions pushing out further and further until walking is near impossible. By far the most painful part, though, is in his lower back, where his spine stretches out, pushing forth a small nub of a tail, taking on muscle mass rapidly until it's nearly a foot long. Over the course of the next day, it continues to grow to his knees, stiff and useless at the moment but still very powerful. To end it all rather anticlimaticly, his mid back begins to ache, a dark cartelidge fin protruding from his back.
The changes end, and yet, through all that trauma, Skye finds that he's still hungry...let's hope that none of his friends are around.