"Now, my dear," Dr. Cockroach said as he leaned over the control panel for his machine, "this will only hurt for a moment."
The subject in the machine, a dainty woman who had volunteered for the experiment for reasons Dr. Cockroach had not been able to ascertain on his own, rested her head coquettishly against the side of the tank, waiting. She even smiled and waved at him. He wondered if she would have the same response once he threw the switch.
Truthfully, it didn't matter to him at all. Mad scientists have little use for the emotions of their subjects. No need in him getting invested with this one. Though he would have preferred a male subject, to make un-doing his failed experiment easier by having, at least, the same basic genetic make-up. He had not taken the time to determine if the sex of the subject was truly relevant, but he was too far into his current cycle of tests to back out without finishing them.
He pressed several buttons, shifted two levers on the left, then threw the main switch to repeat his first experiment. It was at this particular moment that he realized he had failed to mention to his current test subject that she would be required for two tests, not just one. He needed to, first, change her into a cockroach, then, second, reverse the process. He shrugged and continued to monitor the output from the device.
A pop and puff of smoke later, he watched the chamber door open to reveal the woman who had stepped in, sadly devoid of an insectile head, but with crispy hair that stood out in all directions at once. That part was satisfyingly familiar at any rate. He rubbed his finger across his mustache and 'hmmm'd' softly. "I see we'll have to try this one again after a few minor adjustments." He looked at his subject. "Why don't you go have a bit of a rest and I'll come get you when I'm ready to try again."
The woman nodded slowly and exited into the small closet that had been pseudo-converted into a room large enough to hold a small mattress for use as a bed and an over-turned milkcrate for use as a table.
Dr. Cockroach returned to his calculations, going over everything one more time in search of errors or omissions.