Who saw that coming? 

Mount Justice

October 31, 19:34 EDT

Wally, dressed up in a werewolf costume, let out a loud howl, trying to get Wolf to join in. Wolf, however, just snored. Wally turned to the canine in exasperation. "Really? You're not going to join in at all? What kind of wolf are you?"

"Wally, stop torturing him." Conner called to the red haired speedster. 

"Hold still please." M'gann asked her the Kryptonian as she wrapped him in toilet paper. 

"Megan, stop torturing him. Awkward for him anyway, being a third wheel on our date." Wally walked over to the duo. 

"Wally, I invited the entire team to the dance. Zatanna too." 

"Good. Keeps us on the down-low." Wally winked. M'gann and Conner exchanged a look. "So, you going as my favorite Martian?"

"Not exactly." She stepped away and shape shifted into a zombie bride, growling.

"Woah. Babe, eat my brains anytime." 

"Ew." Pietro gagged, walking into the cavern in civvies. "Was that supposed to be flirtatious?"

Before Wally could bite back a remark the zeta tubes announced the arrival of both Artemis and Zatanna, dressed as a vampire and a witch, respectively. Artemis turned to the younger girl. "Oh, hey Zatanna. You look great." 

"Oh thanks, you too." Zatanna replied, walking with her to the quartet in the middle of the room. She looked at Pietro in his street clothes. "Where is your costume?"

Pietro flushed red, rubbing the back of his neck. "Um..."

"Don't tell me you aren't going to dress up." Zatanna raised a brow at the speedster. 

"Guilty?"

Zatanna chuckled. "I can fix that." She pointed her finger at Pietro. "Egnahc S'orteip tiftuo ot a Nietsneknarf emutsoc!"

A poof smoke surrounded Pietro and when it disappeared his clothes were changed to that of a Frankenstein. He looked up at Zatanna with a sly smile. "Your powers will never cease to amaze me."

"Thanks." She grinned back, looking over at Conner and M'gann when they started giggling. Zatanna turned to Artemis. "So, how long have those two been a couple?"

"A couple? Ha! No. They're not a..." Artemis trailed off, looking to the duo.

"Will you please stop fidgeting?" M'gann giggled. 

"You are so making this up to me later." Conner teased. 

Artemis narrowed her eyes and turned to leave, Zatanna chasing after her. 

Pietro watched the girls leave, his heart saddening as Zatanna left his view. He turned to his other friends. "Are Rob and Kaldur joining us?"

"Nope. Too cool for a dance, apparently. Speaking of which, we're going to be late. Let's boogey." Wally said, heading towards the zeta tubes. 

"Did you really just make that awful pun?" Pietro groaned, following after his friends. 

Happy Harbor

October 31, 20:15 EDT

Pietro walked into the dance along with Conner, M'gann, and Wally to be greeted by an assortment of teens in costumes, the majority of which were in costumes of the Justice League members. 

Mal, Karen, Wendy, and Marvin greeted the four other teens. 

"You look amazing!" Wendy grabbed M'gann's hands, the human teen dressed up as Black Canary. 

"Who did your makeup, girl?" Karen, dressed as a bumblebee, asked while looking M'gann over. 

Mal walked up to Conner, lowering his shades. "Burn victim?" 

Pietro snorted. 

"Mummy. You?"

"Superman...done right."

"Yeah, good luck with that." Conner scoffed. 

M'gann turned to introduce the group to Wally. "This is Wendy, Karen, Mal and -"

"Ignore Marvin. He thinks we're being invaded by Martians." Wendy rolled her eyes arms crossed over her chest. 

"I never said that. It's just, reports are all over the interwebs, and I'm not the only one getting them." Marvin, who was dressed as Batman, looked away from his cellphone to stare at the other teens as other cells started beeping. "I mean, Martians aren't invading, it's just a prank gone viral, right?"

"Of course it's a prank. Ever hear of Martian Manhunter? Martian's aren't hostile." A guy standing at the punch bowl added to the conversation.

"Of course not." M'gann chuckled nervously. 

Mount Justice

October 31, 20:35 EDT

"Computer, secure the room." Batman looked at the gathering of Red Tornado, Red Arrow, Aqualad, and Robin. "I'll cut to it. Do we still believe there is a mole within the team?"

"I'm convinced there is none." Aqualad spoke up. "When Cheshire claimed she had an inside source she was merely sowing dissent."

"Her intel could easily  have come from comparing notes with the other villains working for the Injustice League." Robin added. "And think about it, if anyone on this team was working for those creepoids -"

"He or she would have betrayed us during our fight against them." Aqualad concluded for Robin. 

Batman kept his face neutral, his posture relaxed as he listened to the conversation. 

"I'm not convinced." Red Arrow declared. "Sure, you two and Kid Flash are above suspicion, but I know Artemis isn't shooting straight. For starters, she isn't Green Arrows niece."

"What?" Kaldur was shocked.

"Well, yeah." Robin stated as if it were obvious. "In fact, she's related to-"

"Enough. Artemis' relations may indeed make her suspect but she's still entitled to a secret identity." Batman turned from Robin. "I'm more concerned about Superboy and Quicksilver. We still know very little about what Cadmus programmed into their weapons. Either one could be the mole and not know it."

"But Pietro is a meta human. He had a life before Cadmus. How could Cadmus program him if they did not create him like they did Conner?"

"Subconscious programming via the telepathic genomorphs." Robin muttered.

"If I may say something." Red Tornado stepped forward. "After the team retrieved me from Morrow's lab, Pietro asked me a morality question. He asked if I were given the chance to get the thing I most wanted in the universe, but at someone else's expense, would I accept it? He then added to the question, asking if my answer would change if someone else depended on my acceptance as well."

"So you're saying he is grappling with his morals?" Aqualad questioned.

"A hypothetical question is not the equivalent of shifting morals. And was it not less than a week later he sacrificed his life to save another?"

"It was a fake reality."

"He was not aware. At the time, Miss Martian had control of the simulation and made the team forget it was not real."

"And speaking of Miss Martian, she is Martian Manhunter's niece. But he told Black Canary he has a few hundred nieces and nephews. And the first time he met M'gann was five months ago when she stowed away on his last trip from Mars to Earth." Red Arrow pointed out.

"This changes nothing. I have fought side by side with these people. None are traitors." Kaldur spoke with conviction, arms crossed over his chest. 

Batman kept his face straight as Kaldur spoke, knowing the truth. 

Happy Harbor

October 31, 20:47 EDT

Pietro was dancing with the rest of the group when the lights and music went off in the gymnasium, sparking confusion and a murmuring in the crowd, someone saying it was probably just a blown fuse. 

"Says here Martians have taken New Haven and Providence." Mal said, looking at his cell phone.

"Spotted in Happy Harbor too." Wendy added, also looking at her phone. 

"Guys, guys, it's a Halloween cliché." The guy with the eye patch said.

"Meaning it happens a lot?" Karen drawled. 

The loud speaker crackled to life. "Attention, homeland security advises everyone to stay inside the gymnasium. This is not meant as confirmation of any alien invasion." 

We should call the cave. 

Wait. 

Conner stepped away from the group, closer to the bleachers. 

"For your own safety, remain inside." The voice over the loud speaker instructed. 

Pietro looked between the bleachers and Conner. 

What is going on? Is someone back there?

Oh yeah. You guys want to have some fun?

What did you have in mind?

A little counter prank on our friend Marvin. Come on, let's go outside.

The quartet went outside after devising their plan, hiding around the corner of the building away from Marvin, watching as he sent a group of freshmen back into the building. 

Okay, Pietro, you're up.

Cracking his knuckles, Pietro ran around the corner towards Marvin. "The Martians are coming! The Martians are coming!" 

"Look out!" Wally cried out, running out of the building to stand next to Marvin.

"They have a disintegration ray!" Conner added, running with Wally.

"Ah!" Pietro yelled, spinning so fast he was a blur before hiding behind a car. M'gann appeared behind Pietro holding a flash light, her body shifted to look like an unknown alien. 

"Run, Marvin. We'll hold it off!" Conner pushed the teen away, standing in front of him with Wally. 

M'gann used her telekinesis to lift both her friends in the air, throwing them against the ground and the building, before tossing them in front of Marvin, both the teens playing dead. Marvin went running into the school screaming. The quartet stood there laughing, watching the boy run away. 

"That was fun." Pietro grinned widely.

"Heh. Come on. We do not want to miss this." Conner led the group back inside, just in time to see Marvin freaking out to the school. 

"-killed three guys!" Marvin screamed. 

"Which three guys?" M'gann asked.

"Those three guys!" Marvin yelled, pointing at Pietro, Conner, and Wally as they walked up behind M'gann. "Wait...I...uh...oh."

"Marvin?" Wendy crossed her arms over her chest, glaring at the teen.

"Trick or treat?" He shrugged. 

Ha! That was great! We should prank more often.

Dude, you sound like Rob. 

Maybe I'll team up with him to prank the rest of you. We'd be unstoppable. 

Hey, woah. He is my partner in crime. Get your own. 

Pietro glared jokingly at Wally, who smirked at the teen. 

Maybe...Zatanna?

Pietro blushed furiously, ducking his head. 

Shut it.