On the coast of a small part of the Digital World, there was a problem. A group of Hookmon and Mermaimon had somehow misplaced an important treasure at some point, and had began bickering with each other over who had lost it. This was less than fun for other Digimon in the area.
It was even less fun for Joe and Iori, who both found themselves and their Digimon pretty much forced to search through the caves nearby to find it as no one else had underwater Digimon.
Mimi had offered to 'help', but she mostly seemed to be here for the nearby beach.
"Found anything, Gomamon?" Joe asked as the seal returned from an underwater search.
"Uh, some boots."
"I don't think that's their treasure," Joe sighed.
Gomamon tossed them back.
"Mimi, can you swim at all?" Gomamon asked her.
"Yep, but not long enough to look. Lillymon's flying around seeing if there's any land entrances..."
"She's sunbathing behind those rocks over there, actually," Joe corrected.
"Well, she must be finished."
"We've got Iori and Submarimon looking in the caves too, but we're kind of useless on the beach here," Joe sighed.
"Pity we're not mermaids I guess... Hey! I know, that glitch with unecrypted ports where we can customise what we look like or change shapes, we just go back, come in through that, and we can be mer-people!"
"...What?"
"Gomamon, go fetch Iori, we need his D-3 for this!"
"I'll pass..." Joe gulped.
"Spoilsport. Oh well, I bet Lillymon will become MermaidLillymon!"
Moments later, they were back on Earth, in Koushiro's room.
"...I'd love to come with you, Mimi, but someone trailed a lot of sand into my room," Koushiro sighed as he set up the glitch.
"Sorry!" Lillymon said.
"Anyway, it's ready. Try to remember to think of gills or this is a waste of time."
"Uh, do I have to be a mer-boy?" Iori asked.
"Well, no, you can sit in Submarimon still," Mimi said.
The pair re-entered, finding the new portal was slightly over the water, splashing in.
"...Hey, you just went with the same bikini top?" Lillymon asked.
"Yup. But I have a dolphin bottom!" Mimi said, spinning around to wave her now fishy lower half from the water.
"Huh. Oh well, let's go," Lillymon said.
"...Did she become a half-shark?" Gomamon asked Joe from the shore.
"Yes. She did."
"And Mimi's a dolphin."
"Yes, she is."
"...Are you sure you don't want to go become a Mermaid?"
"Merman!" Joe corrected.
"Whatever. It'd be a good help having five of us looking.
"...Fine."
Joe left, and returned. Mimi and Lillymon had waited for him as he splashed down with a yelp.
The pair looked at him.
The pair burst out laughing.
"Joe, did you maybe think of the wrong thing?" Lillymon snickered.
"What... Gha!"
Joe was surprised to look down and discover (s)he was wearing a seashell bikini, as well as having red hair.
"Nice to know what your favourite Disney princess is. Maybe you should go fix that?" Mimi grinned.
"...Y-yeah..."
The portal, however, was a little too high up from the water.
"Oops. Gomamon, go fetch Iori..."
"Never mind, let's just go looking, this is embarrassing enough without anyone else seeing it," Joe sighed.
About an hour later, they had found the treasure, a small underwater channel leading into a cave... with an obvious opening leading to just below where Lillymon had been sunbathing.
"Huh, this cave had a route in through over land after all," Mimi noted.
Joe had sunk under the water to scream blue murder.