Lex didn't even get the chance to run controlled trials.
The depressant had been theory—nothing more. A counter-agent designed to suppress extreme neural excitation, meant to dull emotional spikes at their chemical source. In theory, it should blunt the manic neural cascade triggered by the Joker's laughing toxin. In theory.
In reality? No animal tests. No human trials. No models. Just instinct, chemistry, and desperation.
And Selina hadn't waited.
Before he could finish explaining the risks—before he could warn her about potential neurochemical collapse or respiratory suppression—she had already driven the syringe into her own thigh and pressed the plunger down.
That alone told him how bad the pain had been.
He stood there watching her, pulse steady on the outside, mind racing beneath the cowl. He cataloged possibilities: seizure. Shock. Cardiac arrhythmia. Respiratory arrest. Psychotic break in the opposite direction.
Instead—
The transformation was immediate.
Her wild, uncontrollable laughter cracked mid-note. It softened into something almost natural. Then a normal chuckle. Then a faint smile.
And then nothing.
Her face went still.
Not blank in the Joker's frozen sense—just quiet. Composed. A faint shadow of melancholy settled behind her eyes, like someone who'd just finished crying and was finally breathing again.
Lex frowned slightly.
Did he overshoot the dose?
"Thank you," she said quietly. "That makes three times."
It was the first time she'd ever thanked him without sarcasm or calculation.
He shifted slightly. "You're welcome. Just… doing what needed to be done."
He studied her posture. Pupils steady. Breathing even. No tremors.
"You feeling anything abnormal? Dizziness? Pressure? Numbness?"
"No." She rose smoothly to her feet. "I feel clear."
Clear.
That was the word.
He exhaled slowly. The counteractive model had worked. The depressant wasn't an antidote—it was a neural equalizer. It didn't neutralize the toxin directly; it suppressed the emotional circuitry the toxin overstimulated.
Poison versus poison.
And it had held.
"If Gotham still had a hospital," he muttered, half to himself, "I'd run a full panel."
"Save the white coat routine," she replied evenly. "Do you have any left?"
He hesitated.
"One more dose."
He pulled the second syringe from a sealed case.
"I prepared a backup in case your system metabolized it too fast."
She held out her hand.
"Give it to me."
He paused. "For what?"
Her expression didn't change.
"He likes forcing people to laugh."
A beat.
"I want him to know what it feels like to be unable to."
Lex's eyebrow twitched beneath the mask.
That was poetic.
"That's… tempting," he admitted. "But fair warning—his physiology is unusual. He's resistant to most toxins. Even Scarecrow's gas didn't break him."
"We'll find out," she said, taking the syringe from his hand before he finished.
The lounge door creaked open.
Alfred stood there, hands clasped tight enough to whiten his knuckles. The moment he saw her standing upright, stable—
"Miss Kyle!"
Relief flooded his voice.
"I'm fine," she said gently. "Sorry to worry you."
"Good heavens… that is excellent news."
His gaze shifted to Lex.
"Sir… remarkable work."
Lex inclined his head slightly. "Temporary solution. We monitor."
But he already knew.
This wasn't temporary.
—
The Joker lay strapped to the reinforced bed inside the underground holding chamber. Motionless. Staring at the ceiling like a wax sculpture left under cold light.
The door slid open.
He turned his head lazily.
The moment he saw the black silhouette in the doorway—
"Ha."
Then a sharper grin.
"Imitation."
He tilted his head, studying Lex's armored suit.
"I've got to admit… you really sell it. Almost makes me nostalgic."
Lex didn't respond.
Silence unnerved most men.
The Joker wasn't most men.
"You know," he continued brightly, "I've been thinking. The whole time I've been lying here, I've been reworking the laughing gas formula in my head."
His eyes glittered.
"You're the variable. You're the anomaly."
He clicked his tongue.
"So next time? Oh, I promise—it'll work on you."
Lex filed that away. Mental note: assume iteration upgrade.
"Where is he?" the Joker suddenly snapped. "Where's the real one? Bring him out."
His eyes narrowed.
"…Unless the rumors are true."
A flicker of something almost hungry crossed his face.
"Did the big bad bat finally fall?"
Lex stepped forward.
Selina followed.
The Joker's expression shifted the moment he saw her.
Confusion.
Then irritation.
Then disbelief.
"…No."
He stared at her face. Calm. Steady.
"You took an antidote."
He turned slowly toward Lex.
"That's impossible."
His voice lowered.
"I am the only one who knows the formula. I am the only one with the cure."
His gaze sharpened.
"…It was you."
"You made one."
He didn't even notice when Selina approached.
Didn't notice the syringe.
Didn't feel it.
Not until the plunger was already empty.
He blinked.
"…What was that?"
Selina stepped back.
"A gift."
The Joker frowned.
"Gift?"
He smiled.
Or tried to.
The smile twitched halfway up his face—and collapsed.
His brow creased.
"…Why can't I—"
He inhaled sharply.
Something shifted.
Not physical.
Chemical.
His eyes widened.
"…No."
He tried again.
"Ha."
Nothing.
His mouth trembled.
The grin faltered.
A strange weight crept into his expression. His shoulders sagged.
His breathing changed.
"I…"
His voice cracked.
"Why do I feel…"
His chest tightened.
"…sad?"
The word sounded foreign in his mouth.
Selina watched him with cool satisfaction.
He tried again—forced it.
"Ha."
The sound broke into something closer to a sob.
His eyes darted around the room, frantic.
"No."
His voice rose.
"No no no no no—"
He strained against the restraints, veins standing out in his neck.
"I can't laugh."
His breathing grew erratic.
"What did you do to me?"
Lex watched with clinical fascination.
There was no acting in this. No performance.
The Joker didn't fake emotions—he twisted them. This was something else.
Pure destabilization.
Selina tilted her head slightly.
"You misunderstood me earlier."
Her voice was smooth.
"It doesn't double happiness."
She stepped closer.
"It doubles mine."
The Joker's head snapped toward Lex.
"You."
His eyes burned now—not with madness.
With fury.
"You gave her something."
He jerked against the restraints.
"You think you're clever?"
His voice cracked again, not in rage—something heavier.
"You think you can rewrite me?"
His lips trembled.
"Take off that mask."
His voice rose, uneven.
"Take it off and show me who you are!"
The emotional inversion was total.
The manic energy that once exploded outward now folded inward.
An implosion.
His breathing became ragged.
His eyes shimmered—not with tears, but with something close.
Lex felt it then.
Confirmation.
The depressant didn't neutralize his toxin.
It bypassed it.
It suppressed the hyperactivity in the amygdala and dopamine centers the laughing gas hijacked.
Even his mutated physiology couldn't override that suppression.
At least not immediately.
The question now wasn't whether it worked.
It was duration.
Short-term chemical dampening?
Or structural neurological recalibration?
"Let's go," Lex said calmly.
Selina lingered.
She crouched beside the bed, leaning close to the Joker's ear.
"Enjoy the silence," she whispered.
"I'll visit again."
He didn't look at her.
His eyes stayed locked on Lex.
"Don't leave."
The words weren't taunting this time.
They were raw.
"You don't get to walk away."
His voice cracked completely.
"You don't get to hide behind that mask."
He thrashed once more.
"I need to see your face!"
The restraints held.
The door closed.
His voice echoed behind them, no longer manic laughter—
Just fractured, furious despair.
In the corridor outside, Selina exhaled slowly.
"That," she said quietly, "felt better than any punch I've ever thrown."
Lex didn't respond immediately.
His mind was already running calculations.
Dosage. Metabolic rate. Rebound probability.
If the effect stabilized, he'd achieved something unprecedented.
A controllable emotional inhibitor.
A weapon.
Or a cure.
Behind the steel door, the Joker's voice finally dropped into something small and hollow.
And for the first time in Gotham—
There was no laughter.
....
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