Later that evening, Rarity and Suri were having coffee at the Marebucks cafe where Suri worked her day job. They noticed a large crowd gathering outside and a series of bright flashing lights and loudspeaker music to the tune of "Smile! Smile! Smile!".
"What is all that racket?" Rarity asked.
"It's her. Coco." Suri realized, "She actually planned something, m'kay."
"Planned what? Rarity wondered.
Both ponies trotted outside only for their jaws to drop in awe at the sight of large colorful parade floats, each one having a giant tethered balloon version of the Elements of Harmony/Mane Six attached to them.
"Is that supposed to be me?" Rarity asked, noticing the "Rari-loon", "It really captures my eyes."
"Look! It's Coco!" Suri shouted, pointing with her hoof.
Rarity could barely see Coco, still in her jester costume, dancing around on the last float and twirling her "Coco-cane" scepter. A giant Twilight Sparkle balloon floated above her.
"They really didn't get Twilight down pat." Rarity noted, "Wrong shade of purple."
"Is that candy?" Suri wondered.
Coco was randomly tossing pieces of candy, hard and chocolate alike, to the crowd who nearly trampeled over each other trying to get it.
"The nerve of some ponies." Rarity complained, "Acting like savages over candy."
"At least she isn't throwing bits." Suri said.
As soon as she had said that, a gold bitcoin smacked Suri in the forehead. Coco was now tossing out bits and the crowd was literally bucking and pummeling each other to get them.
"Is she trying to start a riot?" Rarity asked, "Where did all the floats and balloons come from anyway?"
"I think Manehattan was planning a Hearth's Warming Eve parade to honor your friends, m'kay." Suri explained, "Coco must have broken the floats out of storage months ahead of time!"
Suddenly, several ponies in the crowd broke out into boisterous, uncontrollable laughter and collapsed to the ground with frozen rictus grins. Anyone who had eaten the candy was now poisoned with "Smile-Smile-Smile" and died laughing.
"She really is trying to poison the city!" Rarity shouted, "How could Coco even think of doing such a thing?!"
"She isn't Coco anymore, m'kay." Suri said with tears in her eyes.
A stallion galloped up right up to Rarity and laughed in her face then fell out on the street. Rarity tried shaking him but he only laughed even more.
"HA-HA-HA-HA-HA!!" he screamed, "He told me not to eat the candy...but I didn't listen! HA-HA-HA-HA-HA-HA!!"
"Snap out of it!" Rarity begged as she slapped the poor fellow with her hoof.
The stallion did stop laughing, gasped for air, and then died with a fixed smile.
"What in Celestia's name have you done, Coco?!!" Rarity screamed in agony.
"Wait, who told him not to eat the candy?" Suri wondered.
"I did." said an all-too-familiar maniacal male voice, "If anyone's going to kill off this pretty little town with laughing gas then it's going to be me!"
The Joker stepped out of the crowd and grabbed Rarity by the neck. He then held her muzzle right up to the orange flower attached to his jacket and forced her to breath in the knockout gas from the flower. He then ran off with the white pony back into the crowed leaving an echoing trail of laughter.
"HA-HA-HA-HA-ha-ha-ha-ha-ha!!" the Joker screamed.
Suri found the nearest sewer grate, opened it up and swiftly climbed down.
On the main parade float, where Coco was still dancing, one of the ponies who now worked for her, a gruff stallion in mime makeup, trotted up to her.
"Miss Jester." the henchpony announced, "We've still got an active crowd. I don't think they're all eating the candy."
"Time for Plan B!" Coco ordered, "Cut the balloons!"
"Of course, Miss Jester." the henchpony said, "Are you sure about this?"
"We want to make all of Manehattan smile, right?" Coco answered, "Besides, mimes aren't supposed to speak."
Coco slapped the stallion with her "Coco-cane" and the stallion motioned for the rest of the henchponies to cut the balloons. On each float, a "mime" took a knife and cut open the Mane Six balloons, releasing a lethal mixture of helium and Smile gas. Each of the mimes put on a gas mask and waited for the toxin to take effect on the crowd.
Suddenly, a "bat creature" flew through the air and severed the strings on each of the balloons. Batman was gliding along using his cape, also wearing a gas mask. He had sharpened metal attached to the ends of his cape so he acted like a giant batarang. The balloons flew up high into the air, away from anypony's reach, and what little gas had leaked out disappated before anypony could breath it in.
"He stole my balloons!" Coco yelped, "You big meanie!!"
Batman landed on the main float and the mime ponies tried to attack him. Batman easily fended them off, kicking each pony over the side of the float. Coco then threw her scepter at Batman but he blocked it with his cape. Batman tackled the crazed pony and nearly strangled her, holding her neck off the edge of the float.
"What's wrong with you, woman?!" Batman shouted, "Murdering your own kind?! You really are the Joker!"
"Whadda ya gonna do, human?" Coco taunted, "Hold me under the float? Crush me? You wouldn't dare!"
"What makes you think I won't?!" Batman threatened.
"If you can't even kill the mad clown of your own world, then you sure as hay won't kill me." Coco said, "You don't understand. You could never understand. I was going to make Manehattan great again! I was going to make everypony smile and you ruined it!"
Coco then burst into tears and then laughter. She frantically switched between laughs and sobs and Batman realized that a part of her was trying to fight off the effects of Smile. Batman almost considered letting her go but then just simply tied her hooves together with wire from his utility belt.
"Help...me..." Coco pleaded in her normal voice, "Tell everypony...I'm sorry..."
Coco tried to fling herself underneath the float out of guilt but Batman caught her and took the madpony in his arms. He then shot his grappling hook into a nearby building and launched into the air.
Meanwhile, the Joker still had Rarity hostage and broke into Prim Hemline's old office building. He had discovered that this was where Coco was keeping the remaining barrels of liquid Smile and he had his own plans for it.
The effects of the Joker's knockout gas slowly wore off and Rarity fluttered her eyes opened and yawned. She examined her surroundings only to find herself suspended thousands of feet in the air by rope from the side of Hemline's building. Below her she could just barely see the street and dozens of frantic ponies looking as small as insects.
"AAAAAAHHHHHHHHH!!" Rarity shrieked in horror.
The Joker, who was standing on the balcony, stuck his fingers in his ears at the mare's piercing scream.
"Any louder and they might actually hear you in Gotham!" the Joker complained.
"Put me down!" Rarity demanded, "Let me go, you ruffian! What do you want with me?! Who are you?!"
"Oh, I suppose I never formally introduced myself." the Joker said with a mocking bow, "People call me 'The Joker', after the playing card. Actually, that's what I call myself. As for my real name, that's never been made canon. I guess you could say I'm old Guano Man's archnemesis and all, but I prefer to think of it as a professional partnership."
"You're not making the least bit of sense!" Rarity noted, "What do I have to do with any of this lunacy?!"
"You, my pasty equine friend, are bait." the Joker explained, "Sooner or later, either Batfart, the idiot horse that thinks she's me, or your even stupider horse friend that thinks she's Batfart, is going to come looking for you. That's right, I've figured out everything! I plan to kill two bats with one stone! The moment any one of them finds me, I'll be clean away while this whole building is set to blow to Alex Ross's Kingdom Come! In any case, you never did the honor of telling me your name."
"I'm not going to tell you." Rarity huffed, "You don't need to know. Monsters like you never win. Somepony will rescue me."
"I hate to break it to you, diamond butt." the Joker continued, noticing Rarity's cutie mark, "Maybe you're used to such sunshiny optimism in your world, but where I come from people die all the time and 'nopony's' there to save them. Bleh. Now I've started saying 'anypony'."
"Just one question, though." Rarity spoke up, "Who in Celestia's name is Alex Ross?"
Before the Joker could answer, he was once again tackled to the ground, this time by Batmare. Suri had once again donned the mantle of the bat and was pummeling the Joker's face in with her hoof.
The Joker coughed and sputtered blood and his left eye started to go black and puffy. He still laughed in Batmare's face and spat blood that went right up her nostril.
"Disgusting..." Batmare noted, "Now let the poor mare go."
Batmare motioned to Rarity who chuckled nervously.
"Poor choice of words." the Joker said, revealing a hidden Batarang up his sleeve that he had stolen.
The Joker took the Batarang in two of his fingers and flicked it with enough muster in Rarity's direction that it severed the rope suspending her and sent the mare plummeting to her doom.
"AAAHHHHHHH!!!!" Rarity shrieked again.
Before she could become horseloaf splattered on the sidewalk, Rarity felt herself being caught and swept away by a dark blur. She then found herself looking into the eyes of Batman, who had managed to catch her in time, still swinging on his grappling hook.
"AAAAAHHHHHHH!!!!!!" Rarity screamed in Batman's face.
"I'm trying to save you, kid!" Batman shouted back.
Batman let his grapping hook extend as far as it could go as he swung high into the air, Rarity still in one arm. He extended his cape, using it as a glider. The surviving ponies on the ground gasped in awe as the "giant bat" reflected against the moonlight. Batman managed to land on the same balcony where Batmare had wrangled the Joker. Rarity wrestled out of Batman's grasp and hugged Batmare tightly, the only one out of the loony group she trusted.
The Joker slowly struggled to get up, free from Batmare's hooves and faced Batman.
"Well, Batsy! Looks like the joke's on you!" the Joker shouted, "I rigged this place to blow sky high! The bottom floor's full of barrels of that bootleg Smile crud that's nowhere near as quality a product as my Smilex gas! But on the plus side it has some very explosive properties!"
The Joker produced a remote detonator from under his coat which would send another signal to a detonator attached to the barrels to completely collapse the foundation of the building.
"I'm sure you'll escape Bats, but you won't be able to save the hundreds of ponies who can't!" Joker screamed with a maniacal laugh.
The Joker screamed again, this time from a Batarang that cut straight into his wrist, causing it to gush blood and forcing him to drop the detonator. Batman grabbed the detonator and crushed it with his gauntlets, but frowned because was not the one who threw the Batarang.
The Joker clutched his wrist and snarled, looking behind him. Coco, still the Jester, stared him down with a bemused smirk on her face.
"I'm not going to let you have all the fun." she said, "In fact, I won't let you have any. This is my city, you pathetic clod of a clown!"
"Imputent little brat!" the Joker warned, "Who do you think you're talking to?"
"Not a comedian, that's for sure." Coco jibed, "You aren't even good for a laugh."
"I'll rip out your guts and turn them to glue, horse!!" the Joker shouted as he lunged at Coco with mad ferocity.
The Joker held Coco down as tightly as he could manage and squeezed her throat even tighter.
"Laugh, you little equine bitch!" the Joker screamed, "C'mon, LAUGH!! I can't hear you!!"
"Ha....ha...." Coco managed to say as she choked, managing to get one hoof free and jabbing it right into the Joker's throat.
The Joker was forced to clutch his own throat as he was completely out of breath. Coco soon wriggled free and kicked up her hind legs, bucking the Joker clean off the balcony, into the open air.
The Joker tried to scream as he flew off the building, but he didn't have the breath.
"That's...not....funny...." he managed to say between gasps as he plummeted to the ground.
Back on the balcony, Batman peered over the side, looking for any signs of where the Joker had landed.
"I don't seem him." he remarked, "Not good. He's survived worse before."
"How could anypony survive that?" Rarity asked.
"You don't know the Joker." Batman replied.
"I do..." Coco spoke up, "I am the Joker...but I...don't want to be...how do I....?"
"Coco?" Batmare, back in her Suri voice, "Is that you? Are you back?"
"Can't control it..." Coco admitted, "Back and forth....the Smile...is too much...I can't....HA-HA-HA-HA-HA-HA-HA-HA!!"
In her madness, Coco galloped to leap off the building herself but accidentally stepped on the Joker's flower that had fallen off his jacket during the struggle. Knockout gas wasn't the only trick up the Joker's sleeve as the flower also contained a small pouch of corrosive acid. The acid spewed right into Coco's face, covering the left side of it. Coco screamed in agony as half the flesh on her face melted and she pressed her muzzle into the ground.
"COCO!!" Rarity shouted, running over too her and hugging her.
Batman took a small vial of antiseptic from his utlity belt and poured it on Coco's burning face. He then took a strip of gauze and wrapped it as best he could.
"It won't prevent the scarring, but it should prevent an infection." Batman advised, "She needs to get to a hospital."
"I'll take her." Batmare said.
"You'll have to tell the police what happened." Batman instructed, "Do you even have a police?"
"We have a royal guard." Batmare explained, "I know that Coco will have to go on trial. This isn't going to be easy."
Batman spread out his cape into the glider position and prepared to jump from the building himself.
"Where are you going?" Batmare asked.
"I have to find the Joker." Batman said, "More of your kind will die if he's still alive."
"Thank you." Batmare said with tears in her eyes.
"I'm the one that should be thanking you." Batman replied as he lept off into the night.
"So what happens now?" Rarity wondered.
"We bring Manehattan back." Batmare said, "We make Equestria great again."