Suddenly there was a flash of light and a animal that seemed to be mabe out of multiple animals appeared.

"this is great, no way queen chrysalis is going to win now that we have to chaotic beings on our side" siren said sounding really confident

"ok, dad I have some bad news… queen chrysalis is here and is trying to take over this world, and we could really use your help" screwball said

"ok… she probably has an army so we should check to see how big it is" discord said

"ok one sec" screwball said holding the mirror up

"show me queen chrysalis" screwball said into the mirror

The mirror showed queen chrysalis sitting on a thrown in what looked like a cave. But there weren't just changelings there.

"ok she has about 2,000 changelings and this weird looking guy that looks a little bit like a pyramid and is wearing a top hat" screwball said

"uh oh" the twins said

"uh oh, what do you mean uh oh" siren asked

"well that guy you just described sounds a lot like bill cipher" Mable said

"who's that" siren asked

"a villain me and Mable have fought about two times so far" dipper said

"the first time he teamed up with Gideon, the second time he took over dippers body" Mable said

"ok, does he have any weakness's" siren asked

"the only one we know of is that music inflects pain on him" dipper said

"that's great!" siren said

"how is that great" dipper asked

"because I'm not just the princess of the ocean, I'm also the princess of music" siren said

"ok so we probably need some armor and weapons" screwball said

"ok let's get some then" siren said

Siren walked over to a large circular glass structure it opened automatically and she stepped inside and the door closed. Suddenly a flash of white light sirens outfit changed to one that looked like you would find it in a futuristic video game. Her hair was up in two high pony tails. And the armor was pink blue and black. Siren stepped out of the chamber. She was holding a matching futuristic gun.

"ok when you step into this it analysis your body and picks out the best set of armor and weaponry I have that fits you" siren said

"ok… so who's first" siren said

"I guess I'll go first" Mable said after a while

She went in the chamber and the same thing happened, Mable also had her hair up in to high pony tails but her armor was pink, orange and grey. She also had a matching gun. After that eventually everyone had armor on except discord had to change his form in order to fit inside the chamber.

"ok its getting pretty late we should go to bed, well need all the energy we can muster in order to defeat an army of 2000 changelings" screwball said

"Agreed, I'll show you to your rooms" siren said as they walked towards the door

After siren showed she went to check on frost. But when she opened the front doors of the castle frost wasn't there. Instead there was a note in a bottle stuck in the sand. Siren picked it up and took the note out. She began to read the note.

Return to equestria and maybe you'll see frost again.

Love chrysalis

"that's the last straw" siren yelled

"I swear I will make you pay chrysalis" siren said

Siren went back to her room and got ready for bed.

Ok so the sirens armor and Mabel's armor are themed off of 2 of the outfits in hatsune miku's music video game addicts, sirens is outfit 1 and Mable's is outfit 4. And the world isn't in the gravity falls animations it is basically just in anime. If you haven't all ready go watch the gravity falls in anime video (can't remember the name).

That's all

Siren out