A/n: I should tell you now, I'm going to make a lot of cross-overs into the story.

Ford's Pov (finally!)
Too busy ushering everyone to the boat, I barely noticed one body missing. Until I heard disgruntled grunts through the communicators attached to my helmet.

"Can't...break...free!"
"Y/n! Hold on! I'm coming!" Dipper swam out.
"Wait! Dipper!" I intervened, grabbing him by the ankle. "Its too dangerous for you to go, I'll save her."
As if to prove my point, another roar shook the water, even closer this time.
"No! I refuse to let someone I care about get hurt. Not again, not on my watch."
"Ditto for me! I'm not about to let my best friend and Grunkle get eaten by some stupid face island."
The fire of determination enraged in their eyes told me that they weren't going to take "no" for an answer.
"Ok then, let's go!" (I know, its a short one but he'll have more. Promise!)

Mermando's Pov
I was hurriedly swimming through the lake, excited to see Mabel again, when a roar trembled the water.
'Oh no! Mabel!' Picking up the pace, 'She could be in danger!'

A few dolphins swam to my side, a sword, spear, shield, and armor in their fins. I stopped to let them dress me.
"Thank you my friends."
The ones who carried the armor chittered and swam off.
I took the shield and spear then continued swimming.

A huge figure came into view, its top gliding across the water.
Figuring that was the source of the problem, I swam past it to see what it was coming after.
If the thing noticed me, it didn't let on.

A smaller figure appeared, wearing a black diving suit, an oxygen tank strapped to their back, its tube connecting to a helmet, and orange flippers. One of their flippers was caught in a mess of something.
More of these figures were swimming toward them.
My breath hitched. One of them was Mabel!
My heart leapt out.

"Mabel!" She didn't hear me.

NERDLIHCHTUOMYMRETNE
!YNITSEDRUOYRETNE!

Right... forgot about him.
I let out a battle cry and charged.

Your Pov
NERDLIHCHTUOMYMRETNE
!YNITSEDRUOYRETNE!

Another cry soon followed.
I looked to see a half fish, half man? Woman? It was hard to tell due to the long hair, charging the monster.

Then I remembered, "Mermando!" I shouted.
Mabel cried out, "Where?!" She paused and looked around frantically. Finally, she spotted him, "Hey! I'm ov-"
"Mabel! Y/n first, Mermando second" Dipper scolded.

The 3 of them reached me, but not soon enough.
A long, scaly green and yellow tail flew out of nowhere knocking them in the direction of the fight between Mermando and the Island face.

"AAHH!!!!" They all screamed.
"No!"
"Oh yesss, Y/n you are neccesssary to our plan. We can't afford you getting away." A new voice answered.
Suddenly, a weird snake-woman emerged with 4 arms, her 2 main ones each adorned with gold bracelets and spikes, matching ones on her tail. A golden bib with a red outline hung around her extremely long neck, and a matching 3 piece skirt. She had red eyes and a long strip of black hair.
Pop!
Her long, sharp nails punctured my oxygen tank, making me lightheaded.
"What...are you....doing..?" I choked out, my vision grew blurry.
Her tail whipped my helmet off, cutting my eyepatch into 2.
As it fell away, yellow light glowed from my eye, revealing the mark of Bill Cipher. Which just happens to be his wheel. Since you were not a full human, it was much harder to mark you. The only way to do that, was by possessing you.

The tail snaked itself around your waist, gripping you tightly, forcing out all the leftover oxygen in your lungs.
"Oh jussst... checking sssomething."
You blacked out.

I awoken in a cave. It was huge from the looks for it. Probably expanded as you went further back.
Icy cold water splashed against the rocky shores.

"Where...am I?"
"You are at the Nagasss' home bassse my dear." Spoke a familiar voice.
You turned to see the serpent lady from earlier, along with several more right behind her, though they all looked male, all hissing and examining you.
"Who are you?"
"I am Rani Nagi, queen of the Nagasss! And you, are going to help uss!"