Creating an entire script for an episode is a bit ambitious for a single response, but I can certainly outline a detailed scenario for you, including key dialogue and plot elements. Let's dive into this imaginative crossover episode.

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Episode 37: "Kirby's Uninvited Guest"*

Scene 1: *In the Classroom*

Tiff and Tuff are showing a science experiment to their classmates, including Kirby, Susie, Magolor, Taranza, Marx, Adeleine Ribbon, Dark Meta Knight, Shadow Kirby, Drawcia, Elline, Galacta Knight, Cuphead, Ms. Chalice, Mugman, Billie, and Fantoccio, under the supervision of their teacher, who in this fantastical setting, happens to be a wise, yet strict character from the Kirby universe, Professor Whispy Woods.

Just as Tiff is about to reveal the culmination of their experiment, Kirby starts feeling queasy and, to everyone's shock, inadvertently vomits on Professor Whispy Woods.

Professor Whispy Woods: "Goodness, Kirby! Are you alright? This isn't like you at all."

Tiff, with a concerned look: "Kirby, did you eat something strange again?"

Kirby looks embarrassed and nods, muttering apologies.

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Scene 2: *The Nurse's Office*

The School Nurse, a kind-hearted character, perhaps ChuChu (from Kirby's Dream Land 3), examines Kirby and announces, with surprise, that Kirby has a rare parasite.

ChuChu: "It's quite rare to see this kind of parasite in Dream Land. We need to take immediate action."

Magolor, using a hologram tablet, analyses the parasite: "According to my calculations, this parasite isn't from our world. It feeds on the host's energy, which explains Kirby's sudden illness."

Scene 3: *Formulating the Plan*

Gathered in a conference room, the entire gang, along with Professor Whispy Woods and the school principal, Meta Knight, brainstorm on how to remove the parasite.

Meta Knight: "We have no choice. We must venture inside Kirby and face this threat head-on."

Cuphead, energetic as always: "You can count on us! We've faced worse odds!"

Ms. Chalice: "Let's prepare. This is going to be an inside job like no other."

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Scene 4: *The Journey Inside Kirby*

Using Magolor's technology, the team miniaturizes and enters Kirby's body. Inside, they encounter various environments mimicking levels from past Kirby games, filled with enemies that are controlled by the parasite.

The Mage Sisters, alongside Taranza, use their combined magic to clear a path through the hostile cells.

Billie, showcasing bravery: "This place might be creepy, but we won't let that stop us from saving our friend!"

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Scene 5: *The Confrontation with the Parasite*

Finally, they reach the core where the parasite resides, an immense, grotesque creature towering over them.

Fantoccio, never losing his sense of humor even in dire situations: "I've performed in front of tough crowds, but this one takes the cake!"

The battle is intense, with every character using their unique abilities. Kirby, regaining some strength from the encouragement of his friends, fights from the inside.

Peering into Kirby's heart, they see all the friendships he's made, empowering everyone with renewed strength.

Susie, piloting a miniature Robobot Armor, deals the final blow, freeing Kirby from the parasite's grip.

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Scene 6: *Back to Normal*

Back in the real world, Kirby wakes up in the nurse's office, surrounded by all his friends. He feels much better, with no sign of the parasite.

Kirby, in his unique way, thanks everyone.

Tiff: "Just promise us you'll be more careful with what you eat, okay?"

Kirby nods, before everyone shares a laugh, relieved that peace is restored.

The Principal, Meta Knight, concludes: "This adventure has taught us the value of teamwork and vigilance. Well done, everyone."

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End of Episode 37: "Kirby's Uninvited Guest"*

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Keep in mind, while this narrative fits within the whimsical and adventurous spirit of Kirby and his friends, it's a completely original concept and doesn't directly come from any existing Kirby media or Cuphead game.