Disclaimer: I do not own One Piece or the characters, those belong solely to the beautiful brain of Eiichiro Oda. The only thing that can be credited to me is the idea for this story.

A/N: This story was inspired by the fantastic artists on twitter who post images under the hashtag: ワンピース保育園 (AKA, Japanese for "One Piece Nursery"). I highly recommend you search that hashtag and revel in the glory they have created!

"Welcome to The Sandbox, how can—What the hell are you doing here?"

The door thunked shut behind him and Garp grinned, white teeth flashing like a beacon from the middle of his dark beard. The indirect light from the midday sun cast his shadow softly into the room, framing his arm as he gestured vaguely at the interior, "I heard you had started a daycare, but I had to see it to believe it." His eyes were twinkling just as brightly as his mischievous smile.

The ceiling fan thwumped lazily, the air current feathering cigar smoke slowly across his face as he stared silently at the marine. Office chair creaking, he leaned back a bit further to look behind the man as he heard scuffling and immediately said, "Hell no."

Garp burst into laughter, one hand slapping at his thigh, "Oh come on, they're not that bad." He reached his other hand behind his back and shoved a tangled mass of boys across the yellowing linoleum and toward the chipped desk. One of them tripped over his flip-flops and collapsed on his back, his hand flying to stop his straw hat from rolling under the desk. Having secured it to his shaggy black hair, his eyes rolled to look upside down at the face staring at him from over the desk.

He immediately fixated on where the towering man's hands were planted on the fading wood for support and he exclaimed, "YOU HAVE A HOOK FOR A HAND! THAT'S SO COOL!"

Crocodile watched as the boy scrambled to his feet and scampered closer to the desk, a thin layer of dirt making the back of his teal tank top look washed out. His flip-flops slapped the linoleum in a quick tattoo, the echoes from the bare room serving only to magnify how small he was in comparison to the space. The kid tugged his hat absently so it was sitting more securely on his head, then abruptly grabbed at the edge of the desk and pulled himself up to get a better look.

"Luffy!"

The straw-hatted squirt turned to look behind him, "Ace! Do you see his hook? It's so cool, it's like he's a pirate!" He quickly turned sparkling eyes back to Crocodile's face and asked excitedly, "Are you a pirate?"

Crocodile exhaled a cloud of cigar smoke straight into his face, causing the squirt's dark eyes to water. His little hands released the desk as he started coughing. Crocodile's gaze lifted back to Garp as he said flatly, "No."

"Aww, you're not?" Luffy muttered, rubbing the smoke-induced tears from his eyes. His arms pinwheeled as the other dark-haired boy reached forward and snagged the collar of his tank top, dragging Luffy back toward him. The older boy scowled fiercely at Crocodile but said nothing, merely pushing Luffy between him and the blond and then crossing his arms over his shockingly orange tank top.

Crocodile kept his gaze trained on Garp's wicked smile, then sighed and pulled his chair forward to sit down again. He kicked his feet back up on the corner of the desk, crossing them at the ankles, "I'm not taking them, Garp." Crocodile paid little attention to it when the blond boy stuck his tongue out at him, and Garp merely hit him on the top of the head reflexively as he replied without missing a beat, "Come on, Crocodile. I just need you to watch them for today. I've got an important meeting to go to and their usual sitter canceled."

Crocodile leaned back in his chair and placed his hands on his stomach, fingers laced around his hook across his orange and black striped shirt. He turned his face to the ceiling and closed his eyes, sighing out another cloud of smoke, "No."

Garp grimaced and grumbled under his breath, rubbing his chin thoughtfully. As he did so, Luffy managed to break away from his guards and scrambled on top of the desk in a heartbeat. He ignored the hissed "Luffy!" from behind him and scooted until his feet were dangling over the edge of the desk toward Crocodile. The man peaked an eye open as the boy asked, "So if you're not a pirate, why do you have a hook for a hand?"

He shut his eye again, "I never said I wasn't a pirate."

"Yeah you did."

Crocodile opened his eyes and glanced briefly at the other dark-haired boy, only to find the brat had upgraded from scowling to glaring. He had quite the fierce glare for being such a shorty.

The boy opened his mouth to continue, but stopped when he heard Garp snap his fingers. Three pairs of eyes turned to look at Garp (Luffy was still staring intently at Crocodile's hook) as the marine exclaimed, "Ha! What if I sweeten the deal?"

Crocodile eyed the grinning marine.

Garp tugged at the edges of his black suit, straightening the fabric as he said smugly, "If you watch them during my meeting then I'll get those plans you were asking for."

Crocodile's shoes tapped on the peeling linoleum as he lowered them and leaned forward to set his elbows on the desk beside Luffy, linking his fingers around his hook in front of his mouth. His lip curled at the look on Garp's face, his instincts warning that there was a catch, but—

"Fine."

Garp's grin widened, "Excellent! Then I'll be back for them at 5." His eyes dropped to the two boys in front of him and he knocked them both on the head swiftly, eliciting yelps from them both.

The dark-haired one glared up at him, "What the hell was that for, geezer?"

Garp waggled a finger, "I want you to behave, Ace! You and Sabo both!" His eyes flicked to the blond warningly then back up as he opened his mouth to threaten Luffy too because he knew the boy would never… He blinked.

He felt his mouth hang open for a moment, and then his chest heaved in the beginnings of what turned out to be roaring laughter. Tears streaming from his eyes, Garp turned and pushed the door open, shouting over his shoulder, "Good luck!"

Ace and Sabo turned to look at Crocodile and stared. Sabo was the first to crack, his hesitant chuckles devolving into full-blown cackling as he gripped his stomach and pointed. Ace was trying to keep his glare going, but he couldn't resist a couple of snickers, which led quickly into laughter hard enough that he braced a hand against Sabo's shoulder to help hold himself up.

Crocodile stared at the doorway with a grimace, view partially blocked by the small grasping fingers wrapped around his head and slapped over his face. His faint reflection in the glass door revealed the brim of a straw hat skewed strangely on the top of his head, and then there was a pair of eyes underneath them as he felt the boy tug himself a little higher to peek over the top of his head at the doorway. Seeing that Garp was gone, he loosened his legs from their chokehold around Crocodile's throat and planted his sandalled feet on the man's shoulders. Crocodile could feel the boy pushing through his toes, flip-flops almost slipping from their perch on the satin, as he leaned over Crocodile's own head to come face-to-upside-down-face with the man and ask again, "So are you a pirate?"

Crocodile stared at the boy's bobbing head, gaze pulled along the strangely elongated neck (ah, the catch) and he sighed out a cloud of cigar smoke to the side of Luffy's face. Lifting his hook over his head—Luffy's eyes following it in awe the whole time—he snagged the back of the kid's shirt and lifted him forward to stare at him contemplatively. The other two boys tensed as he stood, their laughter silenced abruptly as they eyed him, eyes flicking between his face and their little brother dangling from his hand.

Crocodile turned and walked away, wing-tipped shoes clicking as he made his way toward the back of the room. Luffy was reaching behind his back, trying to get a hold on the hook in his shirt, face twisted in puzzled concentration.

A sharp, angry call burst from behind him, "Where are you taking Luffy?"

When he didn't answer and didn't stop, the quick patter of feet announced the boys' attack. They leaped at his legs, determined to halt his progress, and uttered surprised shouts when they passed right through a cloud of sand and landed on the floor at his feet, right in front of the door in the back of the room. Crocodile halted, rolling his cigar between his teeth as he tilted his chin to glance down at the diminutive humans in his way.

"What the—" The blond stared at his solid-again legs, then lifted his eyes to Crocodile's scarred face and muttered, "You're a Devil Fruit user!" One hand fixing the skewed, ratty black top hat he was wearing, he used the other to prop himself up as his eyes lifted to where Luffy was hanging from Crocodile's hook and he… Sighed in exasperation. Ace was scrambling to his feet furiously, but Sabo merely shook his head and said, "Ace." When the boy glanced back at him, Sabo pointed up. As Ace's eyes rose, his face fell and he groaned, "Luffy."

Luffy had managed to get a grip on Crocodile's hook and had promptly freed his shirt so he could start swinging from the metal appendage like a monkey. Luffy grinned widely at Crocodile and asked, swaying back and forth, "So you're a pirate, right?"

Crocodile felt his brow twitch up and he grunted noncommittally, using his other hand to push open the heavy wooden door in front of him. All three boys turned toward the sudden sound of laughter coming from the back room.

"Mihawk."

At the sound of Crocodile calling his name, the only other adult in the room glanced up from where he was chatting with a dark-haired girl in the far corner, "Hm?"

Two strands of sand pushed lightly at Ace's and Sabo's backs, forcing them a few steps into the room, as a third strand plucked Luffy from his hook and set him gently in front of his brothers. "Three more."

Crocodile vanished as he let the door swing shut and Mihawk turned sharp yellow eyes to the newcomers curiously, his wine-dark pants a stark contrast against the bright yellow bench as he turned to face them fully. The girl sitting on the waist-height bookcase beside him watched them as well, blue-ringed eyes calm and amused. She flexed her bare feet on the back of the yellow bench and leaned forward, resting her elbows on her knees as she propped her chin in her hands and smiled.

Mihawk scanned the two older boys, then his gaze slid to the right as he tracked the one in the straw hat, who had taken one look around the room and shot off like a rocket.

"Luffy!"

"Lu!"

The older two trotted after him, but slowed to a walk and stopped to stand behind their brother as Luffy skidded to a halt next to Mihawk's son and said, "Hi! Want to be friends?"

Zoro continued to practice, his three swords swinging and hitting their targets unerringly as he slid his eyes to stare silently at Luffy. Little Luffy was giving him quite the winning smile beneath his straw hat.

Straw hat… He knew that hat, didn't he?

Mihawk felt his lips twitch.

Zoro's gaze flicked up, a vague frown on his face as he regarded Luffy's brothers scowling at him, although he noted with interest the blond one was watching his movements rather than his face. Zoro suddenly grinned around the hilt in his mouth and halted, breath heaving. Dropping the sword from his mouth and moving all three of them to one hand, he held out his free one and said, mischievous grin still on his face, "Sure, what's your name?"

Luffy slapped a hand into his, that wonderfully goofy grin still plastered on his face, "Monkey D. Luffy! I'm going to be King of the Pirates!

Mihawk felt another tug at his lips. It didn't help that Robin had started chuckling beside him.

Zoro grinned wider, "I'm Zoro! I'm going to be the greatest swordsman in the world!"

Luffy's older brothers groaned and Luffy simply chuckled, a cute "shishishi".

Watching the long-suffering expression on his older brothers' faces as Luffy and his son engaged animatedly, Mihawk couldn't quite stop the amused smirk from sliding across his face.

Satisfied that the three were going to be fine on their own, Mihawk turned back to continue telling Robin about the history of the island he currently called home, their words threaded through with amusement.