Not sure if this idea has been done before due to how many Batman fanfics there are, but I hope you enjoy this. I don't own Batman.
The Clown Prince of Crime clutched his stomach, as blood leaked from the bullet wound. The Joker knew it was pointless, since there were two other bullet holes in his body in places that were definitely fatal. He tried to steady his legs, but he found himself falling backwards until a few bags of rubbish. He observed the pale and sweaty face of the blond man who had shot him, and began to laugh.
"Well, this is a surprise!" he told him, chuckling as he did. "So old Ra's finally sent one of his top assassins to kill me. Took him long enough."
"Who?" the man asked, wiping his brow.
"I have to say, the detail you've put in to make yourself look like some random and pathetic guy is amazing." Joker said. "But what can I expect from the best of the best, though I still wish Ra's had did it himself, I deserve that much."
"I don't know what you're talking about Mr Trickster sir." the man replied, as he approached the Joker and began reaching into the clowns 's coat pockets, being somewhat minefield the weapon in he hands.
"Trickster?" Joker replied in confusion. "What's that wannabe got to do with Ra's? Don't tell me you've confused me with your actual target!"
"Who's Ra's" the man asked.
"What do you mean? Who are you?" the criminal asked in confusion, wondering what was happening.
"My name's Johnny. Johnny Frost."
"Well Johnny Johnny Frost, you have to come up with a better supervillain name than that if you want to make it in Gotham." the Joker told him. "I mean that's why you're here right? If you're not with Ra's you must be some rising super criminal that people don't speak of. Smart move, that way people have no idea who you are or if you even exist.
"I just need some money to buy drugs Mr Trickster." Johnny said simply, though his voice was hesitant and scared.
"Drugs? You after some of the venom stuff Bane is selling. Trust me when I say it's not as cool as he makes it sound."
"Cocaine. Maybe some marijuana. You know, stuff you're probably on Mr Trickster and stuff that's better than what I'm on right now."
"Ok what he fuck is going on!" the Joker yelled in anger, making Frost leap back in surprise and raise his gun at the Joker. "Why are you acting like you're some fucking nobody off the street?"
"Because I am, now shut up!" Frost said with what he had clearly hoped to be an intimidating voice, but it only came out as even more pathetic. And that was when the Joker, the Clown Price of Crime, Batman's greatest foe and Gotham's worst nightmare realized what was happening.
"I've been killed by a good for nothing junkie!" Joker yelled in horror, shaking his head as he tried to push himself back up to his feet. "No way! That's not happening!"
"Stay down Trickster!" Johnny told him, but due to his finger trembling he accidentally pulled the trigger.
"FUCK!" Joker screamed as he clutched his purple gloved right hand, which now has a bullet hole in it and blood leaking out. He slumped down to the ground still screaming. Frost, obviously scared, instantly pointed the gun as the Joker's face.
"Shut up man."
"No fucking way. I can't believe I'm doing this but desperate times call for desperate measures." Joker told him, before taking a deep breath and yelling. "HELP ME! SOMEBODY, ANYBODY! SOMEONE PLEASE CALL THE POLICE! OR BETTER, BATMAN!"
"I said shut up Trickster!" Frost said, before swiftly swinging the butt of the gun at the Joker's face, making him go silent as blood began to drop from his nose.
"Are you fucking kidding me!" Joker yelled in anger, as he felt his body start to feel heavy and it becoming difficult to breath. "You can't do this to me!" I'm the Joker! Not the Trickster, the Joker! Why can't you see that?"
"Because you're not the Joker. You're clearly the Trickster." Frost told him.
"How can you say that? We don't look or sound alike! Never have and never will!"
"If you don't shut up, you're dead!" Frost told him.
"You can't kill me! You're a nobody! I'm the Joker!" the criminal screamed desperately, becoming more and more afraid as he felt his life coming to a close. "I committed crimes using a utility belt that had things such as exploding cigarettes and sneezing powder! I killed one of the Dork Knight's red and yellow sidekicks and crippled Gordon's daughter, who I later found out was Bat-Girl! I fought Clayface and built a suit so I could change just like he could! I even gave fish my signature smile!"
"But most importantly, I became the horror of Gotham!" Joker yelled, hoping someone would hear this and stop it. He tried to ignore the shaking finger at the sun's trigger. "Children wake up screaming of me! People would rather kill themselves and the ones they love than let me get hold of them! If I wanted to, I could easily convince someone to kill their newborn child! I can't die here, at your hands!"
"I'm warning you!"
"But I'm the Joker." he finished pathetically and in a way one could easily call it begging for his life. But it was no use, and the last thing the Joker saw was Frost pulling the trigger of the gun.
What do you think? Tell me if there are spelling mistakes or sentences that don't make sense.