Batmare and the foal wonder!

As Princess Luna approached her destination, she heard the soft thump of heavy bass. This was rather impressive, considering the rooftop party was some twelve stories up. The building in question was made of aged brick, in a construction style not used in decades. It was one of many in this part of town, and would have gone unnoticed if not for the lasers and spotlights streaming out like the spokes of a demented wheel attached to an even more demented form of locomotion. (Some kind of train, perhaps.)

Drawing closer, Luna realized the buildings adjacent to the party seemed to be empty. Something was going on here, where were all the residents? Walking up the steps of the front entrance  she noticed a gruff looking stallion wearing a police uniform standing guard. Had they contacted the police already?

"Let me guess, you got called out for a noise complaint?" Luna asked.

"Noise? Lady, you're crazy, this beat is sicker than grimdark clopfic!"

Taken aback more by the reference that the attitude, Luna tried again. "Ah, yes, it is quite... invigorating. So nopony has filed a complaint?"

"At first we got a bunch of calls, but then everypony who complained got invited to the party, including us! Haven't heard any negativity in fourteen hours or so."

"I see, um... I think I have an invitation, too. One moment...."

"No need, lady, come on in! This here is an open party, all are welcome!"

"Oh, well thank you..."

"Name's Sprinkles, Captain Sprinkles!"

"Thank you Captain."

"Sure thing, Princess!"

Luna paused and looked back at the guard inquisitively, perhaps he knew more than he was letting on. The mysterious policepony had disappeared, however, and was nowhere to be seen. Shrugging, Luna proceeded up the stairwell, she was going to get to the bottom of this, even if she had to climb to the top of the building! As she made her way to the roof, Luna noticed some of the partiers were mingling and dancing on the lower floors, the number steadily increasing as she ascended. This made sense, upon reflection, nine buildings worth of ponies can't all fit on one roof. Finally she made it to a steel door marked 'Roof Access'. She pushed with a hoof and the door squeaked open, but the sound was lost. Instead, her vision and hearing were crushed with a cacophony of curious clamoring and clinquant lights. Momentarily stunned, she stumbled forward into the makeshift party, or had she been pushed?

A pink form finally materialized in front of Luna and raised her hooves above her head in celebration.

"Woo-hoo! Look, everypony, the guest of honor is here!"

The guests all cheered and whistled as the pink pony performed a 'grinding' maneuver on the princess.

Taken aback by the assault to her person and senses,  Luna became indignant.

"Now wait just a moment, what do you think you're doing?"

"Aww," the pink pony answered. " I was just tryin' to dance with ya' Princess."

"You were just rubbing your flank all over me!"

"Yeppers! We call that 'grinding'!"

"Well I prefer not to be 'ground', thank you very much."

"mvmbmbgddcupcakesvmbmbntmntmbg..."

"What was that?"

"Nothing! Sorry about that Princess, why don't you grab some punch? It's delicious, my own recipe!"

"Um... I'm suddenly not very thirsty, what is this whole party about, anyway?"

"Like it? It's my own invention, I call it a Mare-a-thon party!"

"So I've heard, how does it work?"

"Simple, it's a party that never ends! Everypony's invited to attend, and there's no cover charge, isn't it great?"

"That does sound pretty great, so do you have the DJ's and other staff set on rotation or what?"

"Or what! Nopony ever has to leave, that's the best part!"

Luna finally began to really look around at the details of this 'party', all the guests had bags under their eyes, at least the ones that weren't passed out. The DJ had an electric blue mane that would have been stunning if it weren't sagging and straggly from days of neglect. Glancing up, Luna noted more than a few strategically positioned police pegasai patrolling the nearby airspace.

"Ah, so this is a trap..."

"No way! Everypony is here because they want to be! Watch... Hey, anypony want to leave the party?"

A chorus of voices answered in the negative.

"No way!"

"Yeah, this party rocks!"

"It's only been three days!"

Luna looked around in disbelief, how could all these clearly miserable ponies want to stay?

"Hey Princess, why don't you stick around too?"

"I'd love to, but I really should be on my-"

"Hypno-Gator!"

Ah, that was why nopony wanted to leave, Luna thought to herself as she felt the last of her free will drain away. Where did that giant green hat come from, anyway? Oh, there's an alligator on top, what interesting eyes.... swirling, fluctuating, evolving... paaaarrrrrttttttyyyyyyyyyy...

"But Alfalfa! Batmawe hasn't been back in thwee days!"

"And you're still in a body cast my puny pony pal."

"But it's been two weeks, I'm fully healed!"

"Just because some fancy doctor pony says you're fine doesn't mean it's true."

"You just like restraining me, you're weird! I'm going to tell Batmare on you!"

"N-now let's not be too hasty, we think we have the cast cutters here somewhere!"

"That's better." Pipsqueak grumbled.

Alfalfa grabbed the cutting tool and swiftly freed the foal wonder from his bandage bondage. She was more worried about Batmare not punishing her if she ever found out Alfalfa had tried to be dominant. (The horror!) Finally free the fearless foal focused on his goal.

"To the Bat cave, Alfalfa!"

"Of course, master Pip."