Beck got home at the same time as their dad, meeting him at the door. "Hey, Dad," she said. "How was your day?"
"Okay, I guess," said Mr. Hamilton. "How 'bout yours?"
"Pretty darn good," Beck said brightly. "My crush actually asked me out!"
"Congrats," said Mr. Hamilton as her unlocked the front door. "You know, you look kind of different today. No idea why, though." Beck just shrugged, trying to look oblivious.
Inside, Beck found their sister Renata lounging on the sofa with an issue of Cosmopolitan. Beck and Renata were twins, but it couldn't be more obvious that they were fraternal. Whereas, Beck had rejected their female identity, Renata had wholeheartedly embraced it. She had immaculately styled waist-length red hair, great tits, hourglass hips, and a killer wardrobe. She also had a reputation as the school vixen, sleeping with every hottie she met, boy or girl. Only her friend Jezebel du Charme could rival Renata's sexual misadventures.
Beck walked into the kitchen, where their mother was cooking dinner. "Hi, Mom," they said.
Mrs. Hamilton turned around to greet her child. "Oh, welcome home, Beck! I..." She trailed off as she noticed something weird about Beck. "You look... different. When did you get so muscular?"
Internally panicking, Beck fought to sound calm. "Oh, I.. I dunno. I've been working out the pas few weeks."
Mrs. Hamilton put her hands on her hips. "Beck Hamilton, you didn't look anything close to that muscular yesterday. This doen't seem natural. And your behavior's been strange, too. You spent the afternoon at that goth girl's house without telling us, which is bad enough, and then I get a text from Mrs. White telling me you never showed up to class. What is this?!"
Beck was shaking. "I... I cant explain." They sighed. Their parents really were great. They'd been incredibly supportive of Beck when she came out as non-binary, for instance. But they also had an overprotective side, as if they were afraid everything in the world wanted to eat their precious child. Hopefully, this would blow over as they got used to Beck's new muscular build. "I... I gotta go." With that, Beck retreated to the safety of their bedroom.
Once safely in their room, Beck undressed and stood in front of their mirror. With great excitement, they willed their changes to begin. Beck grinned as the platinum-tipped brown fur sprouted all over them like weeds and a wild mane grew down their back. Beck heard their bones pop as their feet elongated and reshaped into paws. As their tail, boobs, and muzzle came in, Beck let their hand stray to their pussy, where the most wondrous magic of all was about to happen.
Beck sighed in ecstasy as their clit began to swell beneath their clawed fingers. Slowly, the nub pushed outwards. Soon it was long enough for Beck to grip, and they began stroking it in the excitement. Just as Beck's clit finished its metamorphosis into a penis, hir pussy moved backwards and hir ballsack sprung into existence. Beck continued enthusiastically jerking hirself off, cackling in pleasure, as the bliss steadily grew into a full-blown orgasm. Beck's cock couldn't contain its load anymore, shooting thick gobs of cum onto the mirror like a cannon. Beck panted, spent.
Beck head hir bedroom door clicking open. Oh, shit! Shi'd forgotten to lock it before shifting! Beck hastily tried to banish hir werehyena form before hir mom saw hir like this.
"Beck," called Mrs. Hamilton, "it's time for dinn... er?" The words died in Mrs. Hamilton's throat as she opened the door to find her child stark naked in the middle of the room. Furthermore, she'd thought for a second she'd seen Beck covered in fairly thick body hair, which had somehow vanished.
"Uhh..." Beck winced. "Hi... Mom?"
"WHAT THE HELL IS THIS?!!" screamed Mrs. Hamilton. "Why are you naked?! Oh my, God, is that semen on the mirror?! Is there a boy here?!"
"No, Mom!" Beck shouted. "There's no boy here!" I really wish I could explain.
"Consider your TV and bike privileges revoked," said Mrs. Hamilton. "I expect you down for dinner in five minutes. PLEASE get dressed."
With that, a very shocked Mrs. Hamilton stormed out of the room. Beck groaned at their own stupidity. Oh well, at least Mrs. Hamilton hadn't straight-up grounded them like they'd expected. Even without a bike, they should still be able to meet up with Selena and the others to transform Brianna. They headed for the closet to get dressed for dinner.