Why Are Zombies So Popular?

In my mind, zombies are so damn popular because of how funny/terrible they can be. For example; in the movie Zombieland, there are obvious humorous things about zombies...the same can be said about Shaun of the Dead and Dead Alive. Yet in both movies, they are still terrible, flesh eating dead people...The interest I have in them is because they are so human. Or they once were...and now they are human bodies run by whatever the story tells you at the time (but the most common thing is solely to be eating living humans). They are like monsters that aren't completely unrealistic...they seem almost probable. I have no idea why people enjoy them so much. But they are all the rage...and I enjoy them too.