So i got this idea for a oneshot, and it amused me so i had to post it.
Unfortunately, I don't own Criminal Minds. Sigh.

I Don't Understand

Jack Hotchner walked into the FBI with his trick or treat bag, ready to show his daddy and his team his Halloween costume.

Once he and his mom reached the BAU, she left, since Hotch was going to be the one to take him trick or treating tonight.

The first person he saw was Emily, and he ran over to give her a hug. She didn't see him coming, but managed to catch him before he could knock her over.

"Whoa, Mr. Hotchner, where are you going in such a hurry?" She questioned the mini Hotch as she lifted him into her arms.

"Hi Miss Emily! I wanna show everyone my Halloween costume!"

She smiled as his enthusiasm, but couldn't figure out his costume. He was wearing a pair of jeans and gray polo and looked like he did every other time she saw him.

"It's very nice, Jack, but what are you supposed to be?"

He whispered it into her ear.

Her mouth dropped open and she had to cover it with her hand to keep herself from laughing. She couldn't help it, and her shoulders started to shake. She finally burst out laughing just as Morgan was walking by.

"Hey Jack, do you know why Em's laughing so hard?" Morgan was a little confused because usually if Emily laughing, Jack was laughing, too. The little boy just looked confused.

"No. I told her what I was for Halloween and she just started laughing." He had a puzzled expression.

"Well what is your costume, Jack? Maybe I can figure out why she thought it was so funny." He couldn't figure out what it could be because Hotch's son looked the same as always.

He looked around, and whispered it into Morgan's ear.

Now Morgan was the one fighting laughter, and Jack just looked even more confused.

Reid walked by and asked what everyone was laughing at.

Jack sighed exasperatedly and answered, "I don't know! Everyone started laughing when I told them what I'm being for Halloween. I don't get it!"

He whispered his costume into Reid's ear, too.

Now Reid looked confused. "You're right Jack; I don't know what's so funny either."

Reid's confusion just made Emily and Morgan laugh even harder. Emily actually had tears running down her cheeks. Garcia and JJ chose this moment to walk by.

"Super Genius, mini Boss-man, what's got these two laughing so hard?" Garcia wanted in on the joke.

Jack sighed again. "I don't know. All I did was tell them my Halloween costume and they started laughing at me. I don't get what's so funny about it. I mean I don't look funny, do I?"

Garcia and JJ shook their heads. "No, you look adorable, like always. But I can't tell what you are, so can you let us in on the secret." Garcia questioned the puzzled five-year-old.

Jack nodded and motioned for them to come closer. He whispered his costume to them.

Garcia took one look at JJ and they burst into uncontrollable hysterics. Jack took one look at them, and fed up, decided to go find his dad. He walked up to his office and found him.

When Hotch heard his son enter, he looked up and found him scowling.

"Jack, what's wrong?"

"Everyone's laughing at my Halloween costume," he crossed him arms over his chest.

"What do you mean?" Hotch was very confused. Even if Jack's costume was funny, which it didn't appear to be, you'd think that a team of adult profilers could manage to control themselves.

Jack took his arm and led him to the rest of the team.

Apparently, they couldn't control themselves. Emily, Morgan, JJ, and Garcia were all laughing hysterically while Reid stood by them, looking confused.

Hotch, getting annoyed since they had upset his son, yelled, "Hey!"

Emily was the only one who managed to control herself for long enough to see Hotch, who looked kinda pissed. That sobered her up a little.

"Look, Hotch, I know you're pissed, but did you ask Jack what his costume is yet?" She had a mischievous smile.

"No, why?" She just smirked, and gestured towards the boy. He raised an eyebrow, but went along.

"Hey Jack, will you tell Daddy what your costume is?"

Jack rolled his eyes and put on a face that implied that Hotch of all people should know.

"Daddy, I'm a serial killer. You know 'cause you told me that they look just like regular people."

The look on Hotch's face was priceless. He barely managed to keep himself together for a few seconds before he burst into laughter. Not even Jack's interruption stopped him.

Jack turned to Emily. "What's so funny?! I don't understand; that's what he said."

Emily smiled sympathetically and picked him up.

"Someday, Jack, someday, you'll understand."