I Am Your Zombie Fan

One day, the actor Duan Feng suddenly received an application to add a friend on WeChat. Duan Feng glanced at the other party's WeChat nickname [I am your zombie fan] and ignored it. But when Duan Feng woke up and checked the class group messages on his phone, he accidentally discovered that [I Am Your Zombie Fan] had automatically added Duan Feng as a friend. In order to prevent others from casually adding him as a friend, Duan Feng had previously set it up to require verification and consent by himself when applying to add himself as a friend. So, how did [I Am Your Zombie Fan] become Duan Feng's friend without Duan Feng's consent? What makes Duan Feng even more puzzled is that Duan Feng tried to delete and block "I am your zombie fan" again and again, but failed. Could it be that there is a virus in my WeChat? What makes Duan Feng even more surprised is that since "I am your zombie fan" became Duan Feng's WeChat friend, his life has become weird. He often feels that there is a pair of invisible eyes watching his every move. [I am your zombie fan] Who is it, why is it interested in Duan Feng, and why does it know so much about Duan Feng's day's experience?