Human beings are not the top-level cognitive agents, there are egregores at higher levels of organization (related to memeplexes, meta-organisms, etc). It's just hard to define and talk about them concretely, our language is not well-suited to reason about agency above the human level. One century-old example of identifying an egregore is the meme "A spectre is haunting Europe — the spectre of communism." It's nothing supernatural, just like a combination of neurons computing each their own thing gives rise to a new agent (human), a combination of humans computing each their own thing gives rise to a superhuman agent (spectre of communism).