Ferb and Phineas were hard at work in the backyard when Isabella pushed the gate opened.
"Hey, Phineas, whatcha' doin'?" She batted her eyelashes even though he had his back to her.
Phineas briefly ducked his head before glancing over his shoulder to give her a quick wave.
"Good morning, Isabella." Ferb slammed a panel on the top of their invention shut. It didn't look like much more than a large metal box a door in one side.
"Uh, morning, Ferb?" Her eyes locked back onto Phineas. "Is he okay?"
Ferb followed her gaze. "Yes, yes, he is. Why?"
"Because you're talking and he... isn't." Two lines in and it was already starting creep her out. Especially, when Ferb's response to the question was to frown deeply at her.
Phineas turned to face her, his face disturbingly blank. Ferb levels of blank.
"Did you switch consciousnesses?" If it happened with Candace and Perry, it could've happened to them.
Both brothers looked down at themselves and at each other before Phineas shook his head.
"Nope." Hearing a popped 'p' coming from Ferb had her flinching.
It was unnatural. Everything about this was.
Okay, maybe they'd done something else. "Did you switch personalities?"
Ferb laughed. Loud. Before hopping off of their invention. "Don't be silly, Isabella."
Phineas clambered up to take his place, reopening the panel as he rolled his eyes.
Her next guess would be that they were imposters but saying that to their faces might not go so well. Skipping it, the only other options were some other kind of ray from the sky or something caused by the metal box. She pointed at the invention. "What is that?"
"That? Oh, we were exploring the possibility of alternate dimensions. But, ah," Ferb paused, scratching his head, "it doesn't appear to be working."
"I think it worked."
Ferb blinked at her. "Wait? Really?" He twisted, looking behind him at it like it was doing something. Realizing it wasn't, he turned back. "What makes you say that?"
Was he serious right now? Did her line of questioning not give him any idea at all? "Because you, neither of you, are acting like yourself!"
A choked noise came from behind him drawing their attention just in time to see Phineas fall off the far side of the invention.
Ferb closed his eyes for a second. "Are you alright?"
A hand popped out from the side, giving a thumbs up.
"Ferb!"
His hands came up between her and him. "I honestly don't know what you're talking about. We're acting completely like ourselves." Lowing them, he gave her a suspicious look. "If anything, it's you who's acting out of character."
What?! She ground her teeth. "It's simple. You're not supposed to be chatty, and Phineas should never be this quiet!"
Phineas came out from behind the box and walked over to Ferb. He tapped him on the shoulder.
Ferb glanced at him before sighing. "You're right. He's right. Clearly, we must have switched with your Ferb and Phineas--"
"Phineas and Ferb."
"Whatever." He waved it off. "We'll go back in and hopefully they'll come out."
Nodding, Phineas shoved his hands in his short's pockets.
"Good. You do that."
There was a zap and invention disintegrated.
They all stared at it. Isabella blinked in disbelief.
"Huh."
Phineas finally spoke, "Well, that happened earlier than normal."
A few moments passed before she realized they weren't doing anything. "Rebuild it! Get them back!"
"No point." Ferb shrugged. "It was keyed to a random dimension. There's very little chance of us finding our own dimension by merely rebuilding it. You best hope is that it didn't disappear on their side and that two portals aren't necessary for travel."
Her horror must have shown on her face because Phineas threw his hands up in a T.
"OK, time out." His blank expression changed to a nervous one. "I think this might've gone a bit too far."
Ferb rubbed his face with a slight nod.
"What?"
"It, um, it was a joke?" Phineas offered. "It sounded a lot funnier when we were planning it out this morning? I mean, we really did plan to do some dimension hopping but it kept breaking." He shrugged. "We got tired of trying to find the problem."
"You didn't switch places with another Phineas and Ferb?" She had to be sure.
"No, it was just a bad joke." He pulled a remote out his pocket. "It didn't even get hit by a ray, I just stuck a self-destruct button on it."
Isabella sighed in relief. She could hug him. Or slap him. Maybe both.
"It wasn't even for you, really. We were gonna do it to whoever came over first."
That actually made her feel a little better. "Any chance you could do it again?" Seeing Baljeet and Buford's reaction might help make up for it.
"Ferb?"
Despite his expression having defaulted back to blank, the mischievous smile was audible in his voice when he said, "Phineas, I know what else we're gonna do today."
