I do not own TMNT.

A/N: The turtles are 10 in this story, fyi.

Mikey was watching a movie on the TV. A boy had been attacked by a robber, but soon, the boy had knocked the robber out cold. "Boo yah!" the boy yelled, sticking his thumbs in his ears and wiggling his other fingers. He stuck out his tongue at the robber too.

Hmm, maybe I should say something like 'boo yah' when I defeat someone, Mikey thought. It had to be something he made up himself though. Something unique that was cool to say that no one else had ever made up before.

Mikey figured that his family could help them. He couldn't ask Master Splinter, since he had gone topside to look for food and the turtles were not allowed to go there, at least not until they were older. Leo and Raph had been fighting earlier, so he couldn't ask them either.

That left Donnie. He was only 10, like the other turtles, but he was as smart as a high school student. Usually, Mikey, Leo, and Raph thought Donnie was boring, but Mikey had learned some of the things that Donnie learned were actually pretty interesting.

Mikey entered Donnie's lab. He almost knocked over a vial with a strange, blue-green liquid, but he quickly straightened it before it could fall. "Hey, Don!" he said, grinning.

"What do you want, Mikey?" Donnie asked, not looking up from his computer's screen.

"Oh. Uh... I just wanted to know what you were doing," Mikey said quickly. He hadn't thought of what to say, and he figured it would be better if he didn't ask for help from Donnie right away.

"Studying the origins of words," Donnie answered. "Right now I'm on the word babushka."

"Babushka?" Mikey said curiously, suddenly interested. "What does that mean?"

"It means an old woman or grandmother. It can also mean a headscarf tied under the chin," Donnie replied.

"Oh okay, thanks Donnie!" Mikey said as he left the room.

Donnie was suspicious by Mikey's behavior. Why would he just ask one question, get the answer, and leave?

Was he up to something? If he was, how would the meaning of the word babushka help him?

Donnie shrugged it off. Mikey was probably just curious, that was it.

Mikey had an idea. Maybe if he combined the words 'boo yah' and 'babushka' he would get a new, cool word!

Booyababushka? No, that sounded like you were saying boo yah to a babushka!

Booyashka? Hmm... that sounded okay. Maybe if he switched the letters around...

Booyakasha? Yes! That was it!

Mikey barged into Donnie's lab. "BOOYAKASHA!" he yelled.

"Booyakasha isn't a word, Mikey," Donnie said.

"Now it is," Mikey said defensively as he ran out of the room, probably to annoy Leo and Raph by saying 'booyaksha' in their faces.

So that was what he was up to! Making a new word! Donnie thought to himself. He chuckled. Mikey was 10, but he still acted like a 7-year-old sometimes.