I don't know where this idea came from. I may or may not continue it.

Hakuba stared. Nakamouri stared. The entirety of the task force stared. Nobody had any idea what to do in this situation. The normally impeccable Kaito KID, who never lost his calm and always had that damned smirk on his face, was throwing a tantrum. In the middle of a heist. Hakuba was sure those were actual tears in the thief's eyes. And the reason for this tantrum? A mysterious black clad thief who was leaning casually against a pillar and tossing KID's target of the night up and down in his hand, an amused smile on his lips.

This thief had randomly showed up in the middle of one of KID's heists a while ago, and had stolen the diamond right out of KID's hand before vanishing. Hakuba hadn't known what to think about another thief showing up, but ever since his arrival, they'd been closer than ever to catching KID. Hell, Hakuba had even managed to handcuff KID at the last heist before he'd slipped away.

And every single heist KID had wound up losing his target to this mysterious thief dressed in baggy black clothing, a black beanie, and a black mask that covered the top half of his face. It seemed that KID had finally snapped tonight, as upon seeing his black clad foe, the white clad thief had started yelling.

"NO! NO! NO NO NO NO NO NO! I DIDN'T INVITE YOU! YOU'RE NOT ALLOWED TO BE HERE! GO AWAY! THIS IS MY HEIST! MINE! NOBODY SAID YOU COULD COME! STOP TAKING MY JEWELS! STOP IT! STOP IT! STOP IT! THEY'RE MINE!"

Hakuba was sure his mouth was hanging open, but he felt glued to the floor as the black clad thief let out an overly dramatic sigh and slowly walked up to the thief throwing a tantrum, pocketing the jewel as he did. When he reached KID, he used one hand to take off the top hat, keeping it angled so nobody could see KID's face while his other came up and ruffled his hair. "There, there," The black clad thief mocked slightly, as though comforting a child, "I'm sure you'll do better next time.". Putting the top hat back on, he avoided KID's lunge for the jewel in his pocket and instead pulled out a chocolate bar, setting it in the white gloved hand.

The blond thought for a moment that KID would throw it at the black clad thief or start yelling again, but was surprised when KID suddenly turned and ran out of the room. Even Nakamouri was too shocked to run after him. The mysterious thief chuckled to himself as he slowly waltzed out of the room with the jewel safely in his pocket.

Nobody followed him.

Kaito sat on his bed, breathing heavily after having trashed his room in his anger. How dare that thief keep stealing his prizes! At least KID always returned them! This bastard of a thief had the audacity to keep whatever he stole from KID. Sniffing and rubbing at his eyes, he glared at the chocolate he'd been given. He knew he should have thrown it away, but it was chocolate.

"Stupid, evil, mean, bastard thinking he's so much better," Kaito grumbled to himself as he tore off the wrapper and took a huge bite of the chocolate bar. "Stupid black mask wearing thief with good taste in chocolate. Getting more attention than me. Ruining my heists. Trying to get me caught. Stupid, stupid head." Finishing the chocolate bar, Kaito laid down and hugged his pillow, still muttering about how mean and horrible the other thief was and how he was annoying for having such good taste in chocolate.

The next morning, Kaito was horrified to see nearly every channel replaying a video of his…outburst…at the heist, followed by the black clad thief's condescending attitude as he treated KID like a child. The media was even calling it sibling rivalry. There was no way that bastard wearing black was his sibling. Let alone his older brother like the news was calling him. Ripping the newspaper into confetti, he sulkily got ready for school. He wasn't looking forward to having Hakuba rub what happened last night in his face.

It's really short, but I just wanted to write KID throwing a tantrum during a heist. Let me know what you thought!