Once he was sure that we were alone, or as alone as it was possible to be in the bowels of SymboGen, he leaned closer, and murmured, “You’ve got to stop dozing off during tests that are supposed to be upsetting, Sal. It’s not normal, and you and I both know they’re watching you for signs of not normal. You don’t want to give them the ammunition that they need.”

I blinked at him, feeling that old familiar alarm beginning to coil around my spine. “The ammunition that they need for what? I thought we already determined that I was just unnaturally relaxed, not suffering from low blood pressure or a fainting disorder.”

Sherman didn’t say anything. He just sighed and let go of my arm, turning to start toward the door back to the hall. After a moment’s indecision, I followed him. Sherman was one of the closest things I had to a friend at SymboGen, but the company was still his employer, while I was a girl who should never have been allowed behind the wheel of a car. If it came down to them or me, his loyalty was already given.

The normal swirl of medical and laboratory personnel filled the hallway, their greetings and chatter making further conversation impossible. Sherman had probably timed it that way, to avoid me asking any more awkward questions. I dogged along at his heels, hugging my bag against my chest, until we reached the next lab, where I was handed a plastic cup by a technician I’d never seen before and directed, firmly, to the nearest bathroom. Very firmly: Sherman led me there and pushed me inside before closing the door behind me.

It’s funny: for a company that made its fortune off a genetically modified tapeworm, the people at SymboGen could be awfully prudish about basic bodily functions. The first few times I had to take a urine test after they took out my catheters, I just dropped my pants and filled the cup right in the middle of the lab. I stopped doing that once it was explained to me why it was inappropriate, but they still acted like there was a chance I might start peeing on everything the first opportunity I got. They were the ones who asked for the urine sample. It’s not like I volunteered it.

There are times when I truly regret not remembering my childhood and the normal human socialization that I have to assume came with it. There are other times when I am frankly glad to be free of all the baggage. Everybody pees, especially when they’re ordered to do so by lab techs.

As soon as the cup was full to the line on the side, I capped it firmly and placed it in the small alcove designed for that specific purpose. Apparently, urine was viewed as so powerful that it could even contaminate shelves through plastic if not properly contained. Once that was safely done, I washed and sanitized my hands before knocking on the bathroom door. “You can let me out now,” I said. “I’m done.”

“Are you quite sure?” asked Sherman. I was relieved to hear the teasing note in his voice. I was forgiven for pushing him before. “Maybe you’re still intending to have yourself an extracurricular widdle.”

“Widdle?” I asked, laughing. “Oh, you so made that one up.”

“Don’t test me,” he recommended, and opened the bathroom door. As in Dr. Lo’s lab, the technician had vanished. Sherman saw me looking around for him and clapped a hand down on my shoulder. “Paul couldn’t abide your radiance, my dear. He fled before he could be blinded.”

I sighed. “The new guys still think I’m a freak of nature, huh?”

“To be charitable, Sal, you are a freak of nature. You survived the unsurvivable, you recovered from the unrecoverable, and you fall asleep when you’re having blood drawn. People who don’t know you like the rest of us do just don’t have a frame of reference for you, that’s all. And they have work to do. Your appearance is good for hours of overtime.”

“Shouldn’t that come with a little light conversation?”

“You’ve come a long way in your understanding of human nature,” said Sherman. “You’ve farther yet to travel. Including, if my memory serves me right, down the hall to the radiology lab. Let’s fill you up with delicious barium, shall we?”

“You’re so good to me,” I said sourly, and followed him back into the hall. Just another day at SymboGen, where there’s no test too small, or too invasive, to run on a captive audience.

Extreme precautions are required when attempting to raise D. symbogenesis outside its natural human host. Modern Intestinal Bodyguards™ never exist outside the digestive systems of the people who willingly ingest them in pill form. Consequentially, they have been keyed to respond to specific environmental cues, and will only develop properly when those cues are present in their environment.

This makes D. symbogenesis both easy to control and difficult to study, due to the worm’s tendency to die as soon as it is removed from the biological safety of its human host…

—FROM “THE DEVELOPMENT AND LIFE CYCLE OF DIPHYLLOBOTHRIUM SYMBOGENESIS,” ORIGINALLY PUBLISHED IN THE STANFORD SCIENCE REVIEW, JUNE 2017.

In an ironic side effect of the Intestinal Bodyguard being used for so much day-to-day medical care, people became very cautious about antiparasitic drugs. Several otherwise popular medicines were removed from the market once it became clear that they could damage the implants, and even casual drug users tended to steer clear of things that could harm their resident worms. No one wanted to kill the goose that laid the golden eggs. People were even more reluctant to kill the worm that kept them healthy.

—FROM SELLING THE UNSELLABLE: AMERICAN ADVERTISING THROUGH THE YEARS, BY MORGAN DEMPSEY, PUBLISHED 2026.