Another one for the Free For All! I'll tell you what the prompt was at the end.

Team RWBY settled into their cabin on the Argus Limited, hoping for a relaxing train ride to their next destination. After the journeys everyone had taken to get to Mistral, anything that wasn't a disaster would be a welcome change of pace.

"Alright, girls, I think it's time for an official team exercise," announced Ruby. "Who wants to play video games?"

Yang looked over at her sister from the bunk above Blake's and nodded happily. She hopped down to the floor and walked over towards her luggage.

"Here, let me help you with that," Blake offered, rushing over to grab Yang's bag. The blonde gave her partner a disappointed look.

"I know," muttered Blake. "You don't need help. I should just give it time."

Yang smiled in reply, Ruby and Weiss leaning over her shoulder with content grins on their faces as well.

At that moment, the door of the team's cabin swung open. Ruby, Weiss, and Blake gasped at the sight of another Yang standing at the door, looking dirty, disheveled, and absolutely furious.

"Yang?" whispered Blake.

"What's going on?" demanded Weiss.

But Ruby was the first to recover from her surprise, darting over to her bag and retrieving Crescent Rose in an instant.

"Alright," she said as she leveled the weapon. "Which one of you is the real Yang?"

"I am!" shouted the newcomer. "She kidnapped me the day after the Battle of Haven and has been keeping me prisoner ever since!"

Blake gave her a suspicious look. "I think we would have noticed if our teammate had been replaced for two weeks."

The disheveled Yang glared at her doppelganger. "Did you notice the fact that she hasn't said anything?"

Everyone turned to look at the other Yang. For a moment she stared back at them without saying anything. Then she pulled a cue card seemingly from nowhere. Written on it in thick black marker were the words "DON'T LISTEN TO HER, I'M THE REAL YANG."

"She makes a good point," Ruby mumbled, pointing Crescent Rose at the disheveled Yang.

"Are you kidding me?" Yang shouted at her sister.

"I'm with Ruby," declared Weiss. "There's no way that an imposter could fool us."

"Well how about this?" demanded the disheveled Yang, crossing the room, before anyone could stop her. She waved her arm at the silent Yang's head, only for it to pass straight through.

Ruby, Weiss, and Blake gasped, suddenly turning on the silent Yang. The apparently incorporeal girl looked at her teammates for a second before holding up another cue card. This one read "SHE TRIED TO HIT ME BUT I DODGED."

"That's not going to fool-" began Weiss, but she was cut off by the bang of Crescent Rose. The bullet deflected off of the noisy Yang's Aura, driving her back into the wall.

"What are you doing?" demanded Blake.

"She tried to hit my sister!" Ruby shouted in reply.

"That is your sister, you dolt!" Weiss shouted back.

"Then who have we been hanging out with for the past two weeks?" Ruby asked.

"Neo!" Yang shouted as she picked herself up off the ground.

Ruby frowned. "I'm pretty sure I killed Neo, but I know how to test this." She crossed the room to stand in front of the two Yangs, ignoring Weiss and Blake's insistence that they had just seen it tested.

"Wha- Hey!" the noisy Yang shouted as her sister grabbed one of her breasts, but Ruby just nodded sagely.

"Yep, these are real," Ruby announced. She then reached over and tried to grab at the silent Yang's chest, but somehow failed. "And that is a nose."

For a moment no one said anything, just staring at Ruby in shock. Then there was the sound of breaking glass, and the silent Yang disappeared. The other girls caught a glimpse of Neo retreating down the train's hallway, but it was too late to stop her.

"Well, I'm glad that's over," Ruby sighed.

"Now wait just a minute!" Yang shouted. "We are going to talk about the fact that none of you could tell that wasn't the real me!"

"I mean…" Blake began sheepishly. "To be fair I hadn't really seen you in a while."

Yang's scream of exasperation could heard all the way to Argus.

The prompt was "One night on the Argus Limited, an enraged Yang breaks into RWBY's room. It turns out Neo kidnapped and replaced her weeks ago, and nobody noticed."