Gumball's P.O.V.
"See?!" Marshall waved his hands through the doorway, fazing through as if he were no more than a hologram.
"What the..." I stepped forward and went to poke him in the chest. My hand passed through his torso, and I raised my hand so that my wrist was sticking out of his face.
"Do you mind?" He floated back, out of my reach.
"But I slugged you. I gave you a good ol' fashioned right hook to the jaw." Marcy pointed out.
"Poke him." I suggested.
She jabbed him in the ribs. "Ow! Gee, thanks, Bubba." He said dryly. I shrugged. "I'm gonna go talk to P.B., okay?"
"We'll come, too." Marcy nodded.
"Let's go." I agreed, walking to the door. Marceline followed me, and Marshall floated through the wall, taking the most direct route to the hallway.
XXX
"What's next?! Is Fionna going to start sprouting fur?! Jeez, it looks like you've got some kind of foreign energy radiating around your body. It's almost... necromatic... but more supernatural than magical. I honestly don't know." Bonnie said, holding a scanner wand over Marshall's chest.
"So, how do I touch stuff, doc? And why can't I?" He asked.
"Well, have you ever shown any... ghostly traits before?"
"Well, I got changed into a ghost once, when I was hanging out with Fionna, but we scared each other and got turned back to normal."
"Standard ghost fright curse." Marceline said quietly.
Bonnie tapped her chin. "Hm... with emotional upheaval between Marcy and Fi, your body will have possibly run drastically low on adrenaline, and used any residual energy you could to keep you going, which could, in theory, adapt your DNA with a ghostly gene, thus meaning that while you still float and more than likely consume pigmentation, your molecular structure can alter it's density and construction at a moment's notice. To do so, it should take a neurological impulse to cross the synapses, particularly of a certain amount of energy- because the brain uses varying levels and kinds of miniscule electric bursts to send information along your body- and depending on the strength of such a burst, that decides whether your form is tangible or intangible."
"Uh..." Marshall's face was blank. "Wait, what?"
"In English, Marsh, you can pass through stuff or punch it if you think about it." I said, translating Bonnie-ese into standard Oooian/Aaaian.
"Oh, cool!" He exclaimed, his eyes lighting up.
"That's what I just said." Bonnie complained. "But you missed out on a lot of important things, Gumball. For example, the explanation of the synapses. By the way, Marshall, you're also sun-proof, because your constantly vibrating molecules can't be hit by ultraviolet rays from the sun."
"Because your molecules are dancing, the sun can't get a lock on it." I explained. He nodded.
Bonnie gave me a dirty look.
"I'm dumbing it down for him, Bonnie." I told her, not unkindly.
"Well, he's not an idiot. You don't need to!" She argued, which earnt a snort from Marceline. She rounded on her. "Listen, Marceline, you're a good friend of mine, but you don't need to treat your brother like a dunce, so back off and leave him be!" She glared at Marcy venomously.
"Hey, hey! Quit it, Bonnie, she's just kidding!" I narrowed my eyes. "Leave Marcy outta this. If you've got a bone to pick with me, fine. But don't start ranting at Bonnie just because Marshall isn't a mastermind like you! We can't all be Einsteins!"