How would 你 react to this?
You've been incubating a parasite in your body for years without knowing and it suddenly hatches. It can send waves into your mind as a form of communication. It threatens 你 that if 你 tried to get rid of it 或者 if 你 tell people it's inside you, it will eat your insides and 你 will die.
It can affect your decisions, your diet, any behaviors if so wants to. Being on it's good side would lessen any of these influence. Any contact with other people will have potential to spread it's eggs, leading 更多 parasitic encounters. 你 dying will only lead the parasite into hibernation until it can cling onto another host.
So, basically 你 got a hyperaggressive parasite inside of 你 that evolved to have a good survival rate.
.....Sorry, I guess I get into a good story mood and monster lore building when I'm procrastinating lol.