A/N: For Emynii, who rolled the prompt from the crossover fic generator.

"Your challenge is to write crossover fanfiction combining Dr. Horrible's Sing-Along Blog and Bill Nye the Science Guy. The story should use tornadoes as a plot device!"

Bill Nye the Science Guy stared at the coming tornado in horror, in shock, and, if Dr. Horrible had to guess, just a little bit of envy. The last time his uncle Bill had made a tornado it had been made of water, and safely enclosed inside two two-liter bottles. This? This was the real deal. This was power. This was victory!

This… was going horribly wrong.

"Just do something!" Dr. Horrible shouted, watching as the approaching tornado picked up a Prius and hurled it into the side of Financial Systems International. Serves you right for driving a Prius, he thought, and then: shit.

"Yeah," Bill Nye said incredulously. "No problem. I'll just stop the tornado."

That's perfect, Dr. Horrible thought. "Really?"

"No!"

And it would have to be in front of everyone, Dr. Horrible thought. Of course. If he was going to be humiliated, why wouldn't it be on an epic scale? Assuming any of them survived this, some pimply little wannabe with a cellphone would have this on YouTube in ten minutes, and that…

That would be bad.

Also bad? Tornadoes. Tornadoes coming very close.

He turned to tell his uncle about the blast ray on the second rack on the third hidden wall in his apartment, but his uncle… oh God. No. First graders.

"Cyclone's not the right word, actually, but I'm glad you brought it up," Bill Nye was saying to the class, taking two proffered Sprite bottles and… oh God. He wasn't…

He was. Bill Nye joined the Sprite bottles lip to lip, held them together carefully, and swirled. The Sprite inside circled obediently into a miniature vortex, the exact duplicate of the one bearing down toward them now. Only bubbly. And harmless. And not going to kill them all horribly.

"Bill!"

Bill Nye sighed, listened to Dr. Horrible's rapid explanation of oh God do it do it now (why wasn't the remote working? It should work!) and headed in for the apartment.

Which is, of course, when Captain Hammer showed up. "So… compensating for something?" he smirked, gesturing to the size of the tornado. "And by that I mean your penis." Captain Hammer held up two fingers, spaced very close together. "It's small."

"Didn't know you were so interested in my penis," Dr. Horrible said before he could think. "So, what? You going to stop that thing? Do the big hero thing? Yeah," he laughed, trying not to puke from nerves. "Go for it. Let's see you go stop the tornado."

Please go stop the tornado.

"Who's the old man?" Captain Hammer asked instead, uninterested in the debris that was beginning to swirl around them.

Dr. Horrible told him.

"Bill Nye?" Captain hammer laughed, putting his (strong) hands on his (slim, manly) hips. "That geezer? I didn't know he was still around. Does he still do the thing with the soda bottles?"

That was the last damned straw. "Bill Nye is a genius," Dr. Horrible snapped, getting into Captain Hammer's face and absolutely not wondering why Captain Hammer smelled like lilacs. "That man is a ninja of science and you will show some respect."

There was a rush of motion from the apartment and a lanky figure skittered out, clutching— oh no, that would never work—!

There was a flash of light and then a counter-wind, and possibly something involving voodoo, and the tornado spun itself into nothingness. Sunlight poured down on them like a benediction from heaven, or at least, like a mass of nuclear-powered gas bathing the planet in sweet, sweet solar radiation.

"You did it!" Dr. Horrible shouted, amazed, and elated, and wondering how in the world that had worked.

"I did," Bill Nye said a bit grimly. When he looked at Dr. Horrible again, it was that terrible Look. The kind he gave astrologers and people who didn't believe in dinosaurs. "Your mother would be so disappointed in you," Bill Nye said.

Dr. Horrible spluttered. "My mo— my mother made me this costume!" he retorted. Then: "Uniform!" he corrected hastily. "It's a uniform. Clearly. Obviously. I mean." He cleared his throat. "What?"

Captain Hammer— and oh, great, he was still around— smirked. "Your mommy made your costume?"

Dr. Horrible's hand clenched around the useless tornado remote. This was miserable. This was excruciating.

This was so going on the blog.