The way he saw it, Joker had a positive DUTY to go to Jump City.
First off, the city dwellers themselves needed him. He'd seen photos of them standing around looking grim at the scene of some big explosion. Imagine! They'd just witnessed a perfectly lovely explosion, and they looked GRIM! Clearly, these people needed his help. Only his special touch could bring smiles to the poor, sad Jumpers.
Second, Robin. The little Boy Wonder was growing up; he'd left the cave to fly on his own! It made his heart (or was that his pancreas?) swell with pride. But still, the little Boy Blunder was away from home for the first time ever. Joker had been young once (he assumed) and knew that it was often lonely that first time away from home. What better pick-me-up than a visit from dear old Unky Joker? Who was closer to the whole Batbrood than he? Why, he'd been the one who'd made an opening for Robin by killing the last one! It'd be a happy reunion…plus, he hadn't killed a Robin in a really long time now. Nothing honked the Bat off quite like a Robin mask spattered with blood! Hahahahaaaa!!
Which brought him to the third point. Villains. The villains of Jump City had tried to kill Robin and his little friends (what were they called? The Tie-Ins? The Teutons? The Tie-dyeds?) on several occasions. The nerve! The audacity! The unmitigated gall! HE was the Robin-killer! These whippersnappers were trying to steal his act! Not that they had any real chance of succeeding. The only ones out of diapers were a 60's throwback, a weirdo who apparently wanted to adopt the Boy Blunder and dress him up (even the Joker wasn't that kind of sick), and Killer Moth. Ha! In Gotham, Killer Moth couldn't even get a table at the Iceberg Lounge, yet in Jump City he claimed top-rank status! These kids today were growing up with no idea of what a REAL master criminal was. And what of the poor townsfolk!? Surely they felt the shame such sub-par villainy bestowed on its victims. Could he, in good conscience, let this continue?
No. For the good of everyone concerned, the Joker –kindly clown that he was- would grace Jump City with his presence. Now to spread the word to his entourage.
"HAR-LEY!! Load up the van with explosives and candy, get the Henchmen and set the VCR to record Cartoon Network! We're going on a roadtrip! Its time to make Jump City REALLY jump! HAHAHAHHAHAHHAHAAAAAA!!!!"
-+-+-+THREE WEEKS LATER-+-+-+-+
Starfire was flying Patrol.
Patrol had been Robin's idea, naturally. The Titans couldn't just sit around waiting for trouble to happen. For one thing, they might not get to the scene in time. For another a vast number of crimes went unreported. Therefore, everyday one Titan was nominated to run a minimum of five sweeps through the city, staggered throughout the day. This allowed the heroes to patrol the city without overexerting themselves.
The Titans enjoyed Patrol, generally. It gave them a chance to get out and really connect with the city they defended, to scout the terrain, and- as Beast Boy was wont to say- "pick up some smokin' chicks!". Starfire didn't understand her green friends desire to attract nicotine addicted poultry, but she enjoyed the other aspects of Patrol. She learned a great deal by observing the inhabitants of the city.
Now, for instance, she was floating above the streets, idly watching the pedestrians. How would it be, she wondered, to be an ordinary citizen of the city? Her name would be… Kori. Kori Anders! Starfire giggled slightly at this. She would be a businesswoman… a fashion designer! Starfire had been enamoured of this career ever since she'd heard of it. She would design many wondrous clothes to be sold at the Mall of Shopping, and have a husband named Robin…
Starfire's increasingly romantic reverie was broken by a scream from below. Her attention snapped back to reality, and she looked for the source of the screaming. She saw a blonde woman in a red pants suit being attacked by two muscular thugs.
One swift beating later, the woman was thanking Starfire profusely. As it turned out, she was a new reporter for the Jump City Journal, a Miss Peggy Liacci, and would the famous Starfire be good enough to give her an interview? Starfire considered the matter. Robin had often encouraged her to speak with outsiders to improve her Earthly social skills, and had also often spoke of the need for the Titans to improve their public image following friend Terra's most hurtful betrayal…
An hour later, "Peggy Liacci" walked away with a notebook full of information on the titans- their personalities, their failings, their likes and dislikes. She walked to a payphone and dialed an answering service. "Tell client J-1 that everythin's A-OK!"
-+-+-+-+ A week Later yet-+-+-+
The Titans sat in front of their colossal television watching Jump City's most popular game show Quiz Me This. It was the one program that all five teens enjoyed. Starfire enjoyed all the "most fascinating facts which may be learned", while Raven enjoyed testing her already considerable store of knowledge. Beast Boy and Cyborg liked the way the host- the Quizzler-made fun of the losing players. Robin didn't care for the show itself (he sometimes called it a Riddler Crime Waiting To Happen) but enjoyed spending time with Starfire.
The host (in a cheesy Riddler costume with Q's where the question marks should be) had just gotten the show going, had finished his opening shtick, and was about to introduce the nights contestants when the set suddenly went dark. Loud screaming was heard, which segued into hysterical laughter...and then silence.
A spotlight snapped on, illuminating a single figure standing in the middle of the (now empty) stage. It was a man, dressed in a purple suit, spats, and white gloves. He wore a wide brimmed hat (also purple) and had his head tilted at such an angle that his face was concealed. He leaned slightly on a cane.
Already, Robin had a very bad feeling about this.
The silence was broken by a woman's voice; high-pitched and childish, with a pronounced Gotham accent. "We innerupt this borin' Riddler rip-off...permanently. Aaaannnn' now, ladies and gennlemen, the man who'll put a smile on ya face whether ya want one or not! The one the only -mah man (sigh)-...thhhhheee JOKER!"
The man on the stage snapped his head up, revealing chalk white skin, a big yellowish smile, dark green hair, and eyes totally devoid of warmth or sanity. A face that haunted Robin's worst nightmares.
"GOOOOOD evening Jump City!" The hateful harlequin yelled, his voice brimming with his typical homicidal glee "We're coming to you LIVE from JCTV studios! Well, some of us are still Live, anyway...HAHAHAHAHAHAAAAAAA!"
The camera quickly panned across the audience. Although fine detail was impossible due to the speed at which the camera was moving, two things were clear to the young heroes. First, all the audience members were wearing disturbing, unnatural grins. Second, they were all very, very dead.
Beast Boy gasped, and Raven grimaced, but the other Titans were simply stunned. No villain in their experience had ever shown such a casual attitude to murder. Joker had just killed more than a hundred people for no purpose and was already laughing about it. Even Slade wouldn't have killed that many except as part of some vast plan, and only if he was certain doing so would bring him concrete benefit. Joker had killed them… because it was the easiest way to get attention? Because he felt it added something to his big entrance to Jump City? To set up that Live joke? Who knew?
"Now, many of the brighter Jumpers are no doubt wondering what a big star such as myself is doing here in your sad dreary little town. Well, I'm here visiting an old friend; Robin, I have witnessed the sad, sad parade of losers that have tried their amateurish hands at killing you. Well, you needn't worry anymore. Uncle Joker will make it all better, and then kill you and your little friends the way you deserve to be killed: with style, flair, and loving attention to your personal needs. HAHAHAHAAA!!
"Until then, I've prepared a little something . Not much, just something to show you that I'm thinking of you. I've rigged a gas bomb in the East Side Mall- in ten minutes and thirty seconds all those stressed shoppers will receive- absolutely free of charge with no money down- a lovely Joker grin! TTFN! HAHAHAHAHAHAAA!!!!"
The screen went black for a moment, before a sign came on that said "We are experiencing Technical Problems"