Kat enjoyed the silence while Dan was in the egg. But she was also thinking about what she would do with him now. She could change him into anything, be it only a body change or transforming him into an animal, a hybrid or even something inanimate.
Half an hour later she finally settled on what to do, Dan wouldn´t notice how long he is inside the egg, so Kat decided to let the changes work slowly over the next hours, enjoying the silence even more. Her brother wouldn´t disturb her birthday. But she made a small spell so nobody would notice him missing, and another to make the egg smaller. When the egg stopped shrinking it was around half the size it had been and Dan wasn´t any wiser on the inside. Then she levitated it to the side of her bed, toppled it over to its side and cast the transformation spell on it. Finally she got ready to celebrate her birthday before leaving the egg with Dan alone for the evening, maybe even longer.
Dan himself really was unaware of all this. He had no idea how much time passed already or would pass until he was released. And he neither noticed anything of the shrinking, toppling over nor the slow changes of his body, as the clothes around him remained tightly bound, but made way if something inside them grew out.
The first part of him that changed were his hands. Slowly his fingers shortened, and after an hour or so there wasn´t much left of them, only short tips. His thumbs had vanished completely. The only part that had grown were his nails, as they had gotten longer and sharper, forming claws on his short fingers. For the next hour similar changes happened to his feet, vanishing his small toes while the rest got around the same length. Another one reformed his hands and feet themselves by growing soft pads on the underside and a short layer of fur all around the rest. So after around three hours Dan had four paws instead of hands and feet. To him it felt already like an eternity, but his body was numb, so he could still not tell he had changed at all.
The changes traveled up his arms and legs slowly. It was mostly covering them in fur until it reached his elbows and knees after two hours. They turned as much as they must to keep Dan on all fours later, changing direction. The upper parts off his arms and legs took an additional hour to get changed, mostly shortening away, so in the end all four legs had the same length.
Over the night the transformation went over Dan's body. It overall got slimmer and covered in fur. His genitals receded into a newly formed sheath, hiding them from clear view. His back bend to further keep him down on all fours next to his legs. A numb formed over his ass and slowly got longer and fur-covered, giving him a bushy tail.
After around ten hours, now in the early morning, would the egg break open now it would reveal Dan as a dog with only his head still human. He would be confused when he dropped down as he still doesn´t know of his changed body. The changes slowly crept up his neck and his human hair shortened to fit with the fur. His ears were pushed upwards to the top of his head while growing bigger and pointier. His mouth slowly pushed out, taking his nose along, forming a muzzle. His teeth grew pointier as his nose got black and wet. The last change, exactly as twelve hours of changing ended, were his eyes. They got bigger and turned bright blue. Now Dan was a full dog in body, still not knowing so.
Kat got back hours after the changes had finished, which she discovered quickly. „Now I have a dog as a brother, maybe one of the best presents next to the power of being a witch. But now I must decide if I make any mental adjustments, change it completely or do nothing and see how you live as a human minded dog.“