This is obviously my first time writing a prediction, so I know there are still a lot of mistakes/plot errors in it. If you'd be so kind to point 'em all out, I'd totally appreciate that. Anyway, I focused only on Sanji and co, because I personally find their current situation more interesting (what Luffy had done was completely expected of him). I purposely made this short because I want to see if I could continue with writing this, and because I'm still trying to give it a more solid plot with better and more interesting fights. XD
Zoro, Sanji-in-Nami, and Brook all watch in horror as The Slime slides closer and closer to them. Snapping to his senses first, Sanji suddenly jumps back, surprising those around him.
Sanji: Brook! Get that samurai out of here, and to some place safe!
Brook heaves the samurai on his shoulder, and playfully salutes Sanji-in-Nami.
Brook: Right away, Sanji-san! But I must say, that really made my heart jump. Even if I don't have a heart now! Yohohohoho!
Brook, ignoring the thrashing Samurai in his arms, quickly scans the area for a cave or crevice to put the freezing man down. Spotting a small cave opening nearby, Brook hurries over to the spot and wraps his coat around the freezing Samurai.
Samurai: W-w-w-w-what about you? Won't you be c-c-cold?
Brook: I would if I still had my skin. But as it is, I am now only bones! Yohohohohoho! Please leave everything to us, Samurai-san.
Without waiting for a reply, Brook rushes back to where Zoro and Sanji now engage the gigantic Slime. The monster "spits" at the three pirates, and a massive amount of toxic substance fly their way. Easily evading the poison, Zoro and Sanji rush towards the Slime, and both pirates attempt to land an attack on the creature. A few centimeters away from thrusting Nami's leg against the creature's gooey body, Sanji abruptly turns her body in mid-air, and painfully freefalls on the snow. Groaning softly, he wonders why he is feeling twice the pain than what he expects.
Curiously, he peers down at where he feels the most aches, and realizes, to his horror and delight, that Nami’s huge bosom had cushioned his fall and received the worst impact in the process. A gush of blood spurts out of Nami’s body as Sanji experiences a massive nosebleed.
Sanji: T-t-t-t-t-the glories of a w-w-w-w-w-woman’s b-b-b-body!!!
Meanwhile, Zoro leaps heavenward, and forcefully slashes his sword against the monster’s body. His eyes widen, and in a split-second, he quickly retrieves it, and propels his body backwards, nearly tripping on a rock. Maneuvering in mid-step, Zoro quickly scans the damage on his sword, and turns his attention to the rock he nearly fell on.
Zoro realizes that what he was looking at was not a rock, but a solidified form of the monster’s poison. Feeling a burning sensation on the sole of his shoe, he instinctively removes it and throws it as far as possible, and buries his foot in the snow, reveling in the comforting cold sensation.
At the same moment, Zoro and Sanji realize just what they are up against.
Now recovered from his blood loss, Sanji retreats and tries to find a place to hide and recover, as the monster advances further. With the same idea in mind, Zoro rushes to where the samurai is, and groans in annoyance as he fully examines his sword.
Zoro: *Grumbling* Damn it. I should’ve known that wasn’t an ordinary slime.
Zoro stabs his infected sword on the snow, and buries it deep enough that only the hilt is visible. He then sits as far away from it as possible, and the samurai understands he must not approach it either.
Samurai: What happened to your other companions?
At this moment, Brook returns, his body covered in ice, and shivering, as he holds something in his arms. He kneels before the two swordsmen, and lays out what actually was the Samurai’s torso. In delight, the Samurai leaps over to his body and tries to bring back some feeling into it, by repeatedly kicking his upper half.
Brook: It was quite tricky, retrieving that torso of yours. Perhaps it was a good thing I had been the one to retrieve it; and in the nick of time, too. The monster has left behind a trail of poison that was slowly polluting the river, and destroying everything else on land. If I had flesh and blood, my arm would certainly have been gone now. Look!
Brook raises his arm and stretches it. The sleeve of his dress shirt is completely ripped off, revealing, literally, his shoulder blades. There are also traces of snow, and charred remains of the fabric. The Samurai and Zoro exchange knowing glances.
Brook: Yohohohohohoho!!! As you can see, the poison disintegrates anything and everything. I am alive only because of the Devil Fruit that would not allow me to die. Even if I am already dead. Yohohoho!
Samurai: By the way, where is the woman that accompanied you?
Brook looks around in worry, but Zoro only scoffs.
Zoro: That idiot. Nami is gonna kill him.
Samurai: You’re not going to look for her?
Zoro: He’s a guy that comes by when needed. He won’t die that easily. Not in Nami’s body, he won’t.
Samurai: What do you mean in Nami’s body?
Zoro presses his lips, clearly not intent on explaining. Taking the liberty to do so, Brook begins to tell of their predicament, and the samurai, albeit slightly baffled, nods in understanding.
Sanji: And it’s also possible that the guy who did this to us was the same guy who made you into… well, that. Trafalgar that bastard. But I guess, I owe him for switching me with my beloved Nami-swaaaan~!
Sanji-in-Nami flops tiredly down the snow. He winces in pain as he clutches his bruising side. He sighs grimly, aware that Nami is going to give him a taste of hell after what he has done to her precious, precious body. At this, Sanji determinedly faces his companions, cutting them off from their questions.
Zoro: Now you know what that monster is capable of—
Brook: Sanji-san, what had happened to you—?
Samurai: D’ya get hit? Are you poisoned? The skeleton guy said—
Sanji: Shut up, you guys! Yes, I now know what that monster can do. And while we’re sitting here, talking and doing nothing, he’s getting closer and closer to us. We’re practically sitting ducks! I recognized, a moment too late, that his entire body is made of poison. I thought it was something I could handle, but not only am I in Nami-swan’s body, his poison can incinerate anything that comes a tad bit too close to him. And no, I don’t think I am directly poisoned, but—
Sanji goes rigged, Nami’s eyes zeroing on Zoro’s feet. The swordsman, feeling the intensity of his colleague’s gaze, follows after Nami’s eyes, and the rest of them are frozen in shock. The samurai scurries as far away from Zoro as possible, and Brook’s arms fly to his head in panic. Sanji gets on his knees, ignoring the sharp pain in his side, and examines Zoro’s now purpling sole.
Sanji: That had better be a really bad case of frostbites.
Zoro glowers, and bites his lip.
Zoro: You idiot. Frostbites don’t cause your skin to turn…. greenish… pinkish… In any case, hand over my swords, will ya?
Nami’s eyes shadowed, Sanji wordlessly approaches Zoro’s swords and grabs one.
Samurai: W-what are you…
Brook turns away.
Zoro: I’ve only read it once when my master once forced us to read about the other ways of swordsmanship. You samurais have this… seppuku, right?
In that one sentence, the Samurai understood.
Zoro raised his arm, prepared to hack away his infected foot...
PS: Part 2 is definitely going to be longer and more detailed than this.