I've done it. I have taken over my host's mental functions. It took some time, but I have finally found the proper
parapsychological secretions needed. I am a
tapeworm. Not just any tapeworm - I am a multi-headed hive mind. There are thousands of my
scolexi lining the
intestinal wall of my
host. We have evolved into one. I release my
segments along with my
eggs; I can stay alive for many, many years.
There was a nexus, for a short while, between me and my host. He didn't understand though, he thought he was becoming schizophrenic. He didn't realize that those little thoughts in the back of his head were me - my hum. It matters not, I have overridden his consciousness with my own. His old self doesn't even exist.
I spend my days injecting my eggs into foodstuffs at the various local supermarkets. No one notices me - I am very good at what I do. No doubt I have infected thousands. Soon my species will be the dominant one. No longer are we content to feed and grow - we now have thought.
I can tell which hosts are infected with my brood - there is a connection between us. I can hear their tiny parasitic minds working together, producing the same low-frequency hum that my host complained of just days before I took over his mind. We smile at each other, and nod - we are very good at controlling our hosts' muscular systems. Also, the processing power of the human brain is a welcome addition to my own.
Before we were merely ride-a-longs, now we are puppet masters. I recently visited a doctor host because I had an interest in actually seeing myself. He put a tiny camera inside my host's intestine; it was beautiful. I saw a vast pink tunnel filled with my white stalactites, wriggling around in harmonious unison.
Just for effect, I had my host cry one single tear.