AN: Quite recently, I've once again become infatuated with the Grim Adventures of Billy and Mandy. The coupling, which I was never before interested in, intrigues me now. :)
On with the oneshot! In the spirit of mindless clichés, Billy and Mandy are 16.

Disclaimer: I don't own The Grim Adventures of Billy and Mandy, or Grim and Evil, or whatever the hell it's called. El Chupacabra, however... :)

The Dog Who Became a Wolf

Change is inevitable. It can be drastic or small, immediate or gradual, but it's going to happen. Change is a part of life, and something that Mandy had become much accustomed to over the years.

The changes that happen progressively, over time, can sometimes be shocking when the middle of the story is taken away.

"Man-dee!"

Of course, some things were never meant to change.

Mandy didn't look up, finishing the chemistry equation she was balancing and ignoring the doofus that was sidling up to her shoulder.

"Heey, Mandy!"

Double replacement reaction...

"Mandy, do you gots corn in your ears? Cuz my mom says that's why my dad can't hear her when she wants the toilet clean!"

Silver has a charge of positive one, making copper negative two...

"Mandy? Mandy! Mandy, Mandy, Mandy!"

Three oxygen products...

"Mandy, Mandy, Mandy, Mandy, Mandy, Mandy, Mandy, Mandy!"

Three oxygen reactants...

"Mandy, Mandy, Mandy, Mandy, Mandy, Mandy, Mandy, Mandy, Mandy, Mandy, Mandy, Mandy-"

Still white-knuckled around a pencil, Mandy's fist swung around and connected with Billy's massive nose.

The boy let out a squeaky cry, stumbling backwards and clapping his hands to his face.

Yes, Billy was still a soft, huge-nosed idiot. But his moments of clear thought were occurring more and more frequently as he got older, and he'd finally grown into his head, though the brain inside still suffered greatly.

"Owww..." the boy in the red hat whined, looking down at his snout as if to check for bleeding. He had that kicked puppy look on his face; the one where his brown eyes get huge and shiny, bottom lip wobbling and brows scrunched together miserably.

Mandy hated that stupid expression.

"Stop bothering me, Billy." She croaked, monotone as gravely as ever. Age definitely hadn't softened her, or her body. Though she had grown, matured, and budded (barely) in the obvious places, she had gained none of the womanly softness that her mother had; Mandy was all sharp elbows and cutting glares, with heavy eyebrows that insisted on being black and hardly a nose to speak of. Her blonde hair was the same; razor-edged and tamed by a plain black headband, and her blue eyes were the same, dangerous and icy. She was still deathly intelligent and violent when came the need.

Billy's hair was the same; bright orange, style-less and sticking out randomly from underneath his color-clashing hat. His cow-brown eyes were still dumb and happy. Though he was significantly taller and had managed to sprout a jawline, Billy was still soft-bellied, big-nosed, and rather unimpressive as a male specimen. He still couldn't pass without Mandy changing his grades in the principal's computer (she couldn't have her servant stuck back in middle school; how would he serve her then?), and he could still shift emotions without a clutch. A grin was already spreading over his face, abuse most likely forgotten. "What'cha doin, Mandy?"

"Chemistry."

"Kim's tree? I know that! That's a private landscaping company categorized under Or-na-men-tal Shrub and Tree Services that's stationed in South Haven, Kansas, and it's in Kansas like Dorothy was in Kansas, but then she wasn't in Kansas anymore cuz she said that to the doggie, and South Haven like the spooky town in Scooby-Doo and the Witch's Ghost; that's my favorite Scooby movie because they get to churn buttah!"

Mandy cut his ramble short by pinching his lips together. "Chem-is-try, Billy. As in science. The same class you're taking. The same homework that you should be pathetically attempting, instead of coming into my house to bother me."

As drool started to pool beneath her fingers, Mandy let him go, wiping her hand on his shirt. "You're disgusting. Get out."

Billy sucked up a string of drool thoughtfully, managing to pull off a frown. "You want me to leave, Mandy?"

"Yes."

"Forever and ever?"

Mandy paused. Where had he gotten the 'forever' part? "Preferably," she answered carefully. Because she could easily find a new servant who would be much less annoying, right?

Billy puffed up his cheeks angrily, and Mandy sensed a tantrum. "Fine. I'm gonna go away forever, then!"

"Okay," she replied to the idiot seething on her carpet.

"I'm serious! I really, really, will!"

"Fine! Make sure the door hits you on your way out!" Mandy scowled, mad at him now for thinking he could manipulate her.

"I'm gonna! I'm gonna go far away and live with the Chupacablahbra in New Zealand!"

"So go. You think I care? You're a pain."

Billy stomped his feet angrily, looking like a child with his face turning red in the effort it took to form his irate thoughts into words. "Y-You're a pain more! You're a meanie and a bully and you don't 'preciate me and you make me feel bad and...and..." Tears of frustration glistened over his tawny eyes, the promise of a long fit.

He was still a child. A puppy, really, always following her and being so sweet and nice even when all she did was scold him. He ate like a dog and whined like a dog and slept like a dog, so why shouldn't she hold his leash?

Mandy wasn't sure why he was bothering her so much now, making murky feelings surface that weren't among the familiar annoyance, anger, rage, or fury. He'd said the same things a hundred times before, and she'd always brushed him off. He forgot within a few minutes, anyway. So why now?

"So if I'm so mean, why are you still here? Get out. I'm tired of looking at you." Mandy pinched the bridge of her nose and waved her hand in his direction to shoo him away.

He was looking at her, and though she knew her face betrayed no emotion, she almost felt relieved when he didn't follow her orders and leave. Why? She didn't feel like exploring it. She just shoved it down like everything else.

In any case, it seemed like Billy was having a 'thinking' moment. His eyes looked almost focused, and his jaw was set stubbornly

"I...I don't wanna go away forever, Mandy..." he admitted, voice reaching that piteous whine that usually meant he was trying not to cry.

Mandy countered him before she realized it. "Why? I'm mean to you, right? Sniveling slime like you shouldn't have to put up with that." Her words were dripping with sarcasm, waiting for him to forget what they had been talking about and start pretending to be made of slime, like he had the last time Mandy called him that.

But Billy didn't. His face turned pink – did he really have to concentrate that hard to think? – and he shifted nervously from foot to foot, glancing everywhere but Mandy.

With his odd behavior, Mandy was ready for just about anything.

"I really like my hat, Mandy."

Except for that. Curling her lip, Mandy said, very intelligently, "Huh?"

Billy, staring at his shoes, pointed to his battered old hat, which miraculously matched his face at the moment. "My hat. I really, really like it. That's why I wear it all the time. Even though it's too small and it pinches my head so hard I think my brains are gonna squoosh out. I wear it every day cuz I really, really, really like it, and I don't want no one else to have it 'cept me."

Mandy stared at him for a few moments, digesting his speech and his scarlet cheeks and his odd behavior. It clicked.

"...You're an idiot, Billy."

Said idiot smiled from ear to ear, finally meeting her gaze. "If I be real, real, quiet, can I stay here with you?"

Mandy sighed, swiveling her chair around to face her desk and unfinished homework. "Yes."

She felt him sit down on the floor next to her, his head leaning into her side. She supposed, given the day's events, that she could allow the contact.

"Forever and ever?"

Mandy froze.

She would admit that it would not be in either of their best interests to part ways. She needed him to serve her every whim, and he needed her to save his sorry hide every other day.

So often, it seemed like Billy would get himself tangled up in the nefarious plot of some backwater underworld villain and try to make friends with the carnivorous, ugly beast that was trying to digest him. Then Mandy had to save him. She always saved him. Exploring the reason why never seemed like an intelligent option. Billy was just the best candidate for brainless henchman that she had at the moment.

Mandy permitted herself to glance down at him. He was leaning his weight against her with a sleepy smile on his face, looking as content as a puppy at the feet of its master. The hat he had pledged his loyalty to moments ago sat loosely in the hand that nestled in his lap, leaving his matted hair to stain sweat marks onto her shirt.

In many ways, Billy was still the little boy who had rung her doorbell without noticing she had answered it and proposed to her with a pink balloon. He was the same moron who danced ignorantly through life and clung to the cruelest people as if they were saints. Mandy didn't know if it was because he was really that stupid, or if he saw something in them that no one else did. Her included.

But he was different, too. He was a man, now. The way he approached things were different, and Mandy cursed his ability to manipulate her feelings.

"Forever and ever?"

Mandy knotted her fingers in his hair and mussed it around as if she was angry, earning only a giggle from Billy.

"Not on your life, nimrod," she replied.

Billy only smiled, snuggling his face against her, as if he knew exactly what she had meant to say.

AN: In case you didn't catch Billy's extended metaphor, let me give you a hint. Mandy=hat. Interpret it however you want it to be, romantically or friendshipally. :D Leave me a review, please, and let me know if you liked it!