"The greatest evil scientists have always tested their experiments on themselves first!" Doctor Horrible proclaimed arrogantly, pacing the room. "Bruce Banner! Doctor Jekyll!"

"Same person, dude," Billy muttered from the corner of the room.

"What did you say, worm?" Horrible rounded on his alter ego.

Billy sighed. "The Incredible Hulk is just another version of the Jekyll and Hyde mythos. Same story, wrapped up in a modern package. It's like… Fight Club?"

Horrible gave Billy what he probably thought was a withering stare.

Billy rolled his eyes. "Come on, man! You know this! Hello? You're me!"

Horrible crossed his arms and stuck out his bottom lip. "Am not!"

Billy muttered. "Jesus. Did I get all the brains in the family?"

Horrible tilted his head. "What did you say?"

Billy shook his head. "The red coat makes me look stupid. I never realised that until now. I guess you get a different perspective when you're completely out of your own mind." He let out a hollow chuckle, so different to Horrible's ridiculous laugh. "You think you're dark, don't you? You think you're impressive. But you never realised that all the true power, all the true evil in this relationship, it all comes from me. You're just the puppet. You're the acceptable face of Billy-"

"I'm a valuable member of the Evil League of Evil!" Horrible protested. "I do valuable work."

"Seriously?" Billy said with a smirk. "You just said valuable twice!"

"Shut up!" Horrible snapped.

"And you smell! Jesus Christ, I had no idea. When was the last time you did your fucking laundry? Is this about her? Is this about Penny?"

"Shut up!" Horrible screamed.

Billy just shrugged infuriatingly. "You suck, dude. Just accept it."

Then Horrible did something completely unexpected. He slapped Billy hard across the face.

--

Billy looked down at the vial of liquid in his hand. "Interesting…" He muttered, blinking a few times and massaging his cheek. Jesus, that hurt.

But now Doctor Horrible was nowhere to be seen.

Was he really gone? Was he finally, finally gone?

The experimental formula had been a risk, it was true. A gamble that even now he wasn't sure had paid off.

It was true that Jekyll had probably gone mad. He'd certainly been misguided. But he'd had a damn brilliant idea when he'd decided to try and chemically destroy his own dark half.

He's just been on the wrong side, that was all.

Doctor Horrible had been a plaything, a childish whim. Without him, Billy could be free to plunge the world into terror. Starting with that pretty red-head down the hall.

And yes, she reminded him a little of Penny. But this time there would be no Captain Hammer to distract him.

And there would be no one to protect her.

--

Half way out of the door, Billy felt a cold draught across the back of his neck. He turned around and walked back inside, wondering if he'd left a window open? He tossed his keys into the air and caught then. He tossed them up again.

A hand shot out and snatched the keys right out of the air right in front of him. A black-gloved hand. And hand that balled into the fist and smashed right into his face.

"You do not get to do this!" Came a disembodied voice, as cold as winter, as heavy as the grave.

A fist smashed into Billy's stomach, sending him staggering backwards through the door into his lab.

"You cannot destroy me!" The same hand smashed into his kidneys, doubling him over, making him lose his balance.

"And I do not… smell!" The death ray lifted itself from the workbench and aimed itself at Billy, square on his forehead. The red laser sighting made his eyes water.

Well, at least he didn't end up fucking himself this time!

Billy sighed.

Experiment 83: Total failure.

"You're mad, you know that?" Billy looked up, expecting to see Doctor Horrible standing there.

"Listen to yourself. It's your own lips moving."

Billy's hand moved to his lips. Yes, they moved beneath his fingers.

"Completely insane," He said to himself.

--

Later, as Billy unbuttoned Doctor Horrible's red labcoat, revealing a surprisingly toned body and a good length cock, he wondered vaguely what was really happening when they did this. Was he masturbating? How was it that he felt the kisses, the wet patches left on his own skin by Horrible's open mouth?

How was it that he could taste Horrible's semen for hours afterwards?

Someone should probably study him as an interesting subject - a great example of complete psychosis. But, of course, if anyone ever got close enough to realise what was going on with him, he'd have killed them long before they got a chance.