When I was younger I used to play creepy games with myself where I’d pretend that everyone else except me was an alien. Eventually the fun wore off and I turned to reading SF and comics to get my share of those kinds of thrills, but the idea stayed with me: What if I am not like everyone else? Worse, what if that guy over there isn’t like anyone else except me?

This is a big part of the appeal Parasyte has held for me through its first two volumes — the idea that something can look like a human, behave like a human, and yet somehow be completely alien underneath. Rather than stop there, though, each successive installment of Parasyte has expanded on the idea. Assume that there are humans among us who have been invaded with alien beings — what then? How do they mingle among us undetected? What happens when some of them merge incompletely with their hosts?