Dr. Harleen Quinzel has just joined Arkham as a psychiatrist. Jonathan Crane is her superior. She almost immediately takes an interest in Joker, but Crane says "I recommend you keep a distance from that one. I've seen him drive other inmates further into insanity."
So Harleen does her thing with, questioning all the inmates until one day Crane asks her a favor. "I have a special request. I want you to test this for me. Two-Face to be exact." Said Crane, gesturing over to the large cylindrical object next to him.
"Well, what is it?" asked Harleen
"You'll see, Dr. Quinzel." Crane replied.
"Oh and take this as well. You'll need it." Crane said, tossing Harleen a gas mask.
As she entered Two-Face's cell, Harleen puts on the gas mask Crane provided, and unleashed the contents of the object.
When she did, Two-Face entered a psychotic breakdown while saying stuff like "No! I am in control!" and "My coin. Where's my coin?"
Harleen was horrified by the sight of Two-Face's reaction. She turned off the gas and immediately went to question Crane.
"What was that stuff? And why did you make me test it out on a patient?!" Harleen exclaimed.
"That was fear toxin Dr. Quinzel. My own creation." Crane replied with a grin.
"I made it to cause anyone who breathes it in to have hallucinations of their greatest fears. That was actually the first time I tested it. I'm so glad it works." Crane continued, his grin becoming more and more crazed.
"Dr. Crane sir, our job is to understand the patients and to hopefully make them into better people. This fear toxin will only make their condition worse!" Harleen protested.
"Oh please Dr. Quinzel. The patients here are beyond saving. They're too far gone, I thought patients like Victor Zsazs and The Joker would have taught you that much." Crane replied with a smirk.
"Moving on. I tested it on Two-Face because he was an easy target, what with that duel personality and his obsession over that stupid coin. If it was going to work with anyone, it was going to work with him. Now that I know that it works, I can properly continue with my experiment. Dr. Quinzel, you will continue using the fear toxin on inmates. The next subject will be The Ventriloquist. If it works with him, it should affect his little puppet as well."
And so the tests continued from inmate to inmate. Mr. Freeze, The Riddler, Man-Bat, Cobblepot, Clayface, Bane. Poison Ivy managed to overcome the toxins effects and tried to kill Harleen because it was killing her plants. Catwoman had managed to escape Arkham before she was tested.
One day Crane had a certain inmate in mind for the next test. "Doctor Quinzel, I'm going to have you test the fear toxin on The Joker today. I must confess, I've been looking forward to this part of the experiment."
So, Harleen took the gas to Joker's cell and when she did, the Joker immediately struck up a conversation.
"Hello Ms. Doctor. What brings you to my humble abode?"
Harleen tried to ignore him, instead focusing on setting up the experiment.
"I might be imagining things, but I swear I've been hearing more screams of torment recently. I'm not complaining but I wonder what it's all about. Did ol' Zazzy break out of his cell again?"
Harleen continued ignoring Joker, much to Joker's annoyance. He became fascinated with the fear toxin's container.
"Say, that looks like a fun toy. What's in it? What does it do?"
Harleen responds by unleashing the fear toxin on Joker
"Euugh. It releases a bad smell is what it does."
Harleen is confused by Joker's reaction, as Joker looks mostly disappointed.
"Tell me Ms. Doctor, what exactly were you hoping to accomplish when you released... whatever this is?"
"It was supposed to give you hallucinate something that strikes fear into you."
"Ooooh, that does sound like fun! I should use it for my next grand event with some of my own personal touches of course." Joker said giddily
Harleen exits Joker's cell and goes to ask Crane's thoughts on this.
"It appears that the Joker isn't affected by the gas, sir. What are your thoughts on this?" Harleen inquired.
"I suppose that the clown's mind has become so twisted overtime that he has nothing to fear." Crane speculated.
"Disappointing, but fascinating. I wonder if a stronger dose would get a reaction out of that clown." Crane pondered.
After that Crane continued his experiments. He eventually reached a point where he had tested every inmate and was testing every inmate for a second time. He did so until one day, he called Harleen into his office.
"Dr. Quinzel. I'm unhappy."
"Why's that, sir?"
"My experiment has reached a dead end. I've tested every single inmate here and testing them again isn't getting me any new data. Not even with a stronger dose."
"Well if you ask me sir, I would have thought testing only a few inmates would be enough."
"No no Dr. Quinzel! Each person has their own reaction to the fear toxin. I want to see every reaction there is. I need to know. The problem is that I'm limited to this fucking asylum! I want to test this on more people than the ones already in the looney bin."
Crane was silent for a few moments, until... "Wait. Who says I have to limit myself to just Arkham? I can just release it wherever I want. All I need is my own gas mask."
"But sir, that's-"
"Illegal?"
"Yes!"
"Dr. Quinzel, if I was concerned over if it was illegal or not, I would never have run the tests to begin with. I stuck with the inmates at Arkham because nobody would care what happened to them. I'm just expanding my horizons at this point. After all, Gotham is so infamous for being a nest of criminals, it's a punchline. The world wouldn't care if something like this happened in Gotham."
Harleen couldn't believe what she was hearing. Her superior, the one she worked with for months, was planning to unleash this inhumane drug on all of Gotham. She knew what she had to do. She had to report him to the director.
Ending one:
"Dr. Crane. I'll have to report you to the director for your blatant disregard for the lives of the inmates."
"Is that so, Dr. Quinzel? But aren't you forgetting that you were involved with my tests as well? After all, you were the one who released the toxin."
"If I get fired as a result of reporting you, then so be it. I can't let this slide."
"How bold of you Dr. Quinzel, but I'm afraid I can't let you leave after hearing all this."
Crane got up and grabbed a gas mask and went for the fear toxin. Harleen tried to run, but she was pinned down by Crane.
"You'll be my first test subject who hasn't lost their marbles Dr. Quinzel. You should be honored." Crane said with a muffled voice due to the gas mask.
"And since your so special, I'm going to go ahead and give you all of the gas left in this tank."
Crane attached an oxygen mask to the fear toxin tank and forcefully shoved it on Harleen. She was forced to breathe in all of the remaining fear toxin. She was screaming so loud, it could be heard throughout all of Arkham. She was flailing her body around for all the good it did. She was kicking and screaming until eventually, the overload of fear toxin knocked her unconscious.
-Two Weeks Later-
Two figures lurked outside Gotham Cathedral. They set forth with a bunch of canisters, full of fear toxin. The figures, formerly known as Dr. Jonathan Crane and Dr. Harleen Quinzel, were now known as Scarecrow and Nightmare. One dressed as a scarecrow using a noose as a necklace, and the other dressed as a clown with the main colors being orange and black.
"You know Nightmare, I'm surprised you went with a clown theme for your outfit."
"Well Mr. S, clowns are well known for bein' scary and all that. I wanted an outfit that was ideal for scarin' and I landed on clowns."
"You can't fool me. It's because of your obsession with the Joker isn't it?"
"Maybe, but that's besides the point. We're trying to give all of Gotham a good scare. That's why we're doing this."
"Yes. And it starts with releasing my fear toxin in the big locations. The Gotham Cathedral is a start, but next we go for the Gotham casino, Gotham bank..."
"And Haly's Circus. It is in town this season."
"Yes... Give some travelers a taste of fear."
Ending two:
"I have to go now." said Harleen
"Oh. OK. Be sure to come back soon. We'll be starting up the tests again soon." Crane shouted behind her.
But Harleen would not be coming back for the tests. She was going to put a stop to the tests, and to do that, she was going straight for the director of Arkham Asylum, Jeremiah Arkham.
"But I don't understand sir. This was simply an experiment on the psychological effects on what fear can do to a person. I don't see this as that big a-"
"Silence Jonathan Crane. You are supposed to be curing these psycho's, not driving them further into insanity." said Jeremiah.
"Come one Dr. Quinzel. Back me up. What I'm doing is-"
"That's enough out of you, Jonathan. You're fired. Be grateful you aren't being thrown into a cell yourself." said Jeremiah.
"Yes sir..." said a dejected Crane.
"Thank you for bringing this to my attention Dr. Harleen Quinzel."
"No problem sir." said Harleen
"Though this does mean we will need a new chief psychiatrist. I wonder if Hugo Strange would be willing to come back here?"
-Two Weeks Later-
Dr. Harleen Quinzel continued her work at Arkham Asylum. However as time passed, she began to notice news stories with subjects along the lines of "A group of people suffer psychotic breakdowns. Cause Unknown." and these articles always mentioned someone with a strange mask being seen shortly before the psychotic breakdowns.
While the public had no idea who this was or what was causing the breakdowns, she did. She recognized the symptoms.
"Doctor Jonathan Crane... he went and did it." Harleen said to herself.
"I wonder if it really was the best idea to fire him. If he was going to go and do this anyway, it might've been better if he just kept doing it to the inmates. It would've delayed his public attacks at least." Harleen pondered.
"Batman can't do anything about this. He's susceptible to it as well." Harleen thought.
"There's only one person I know who's immune to the fear toxin, but letting him deal with it is... no it's the only way." Harleen declared.
Harleen made her way over to one of the inmates cell. She knew she had to do something about all this.
"Welcome back to my home Ms. Doctor. What brings you here?"
"As much as I know it's a bad idea, I need your help Joker."