With their huge wings, fat bodies and blood-red eyes, cicadas can look like something out of H.R. Giger nightmare. But they’re completely harmless to human beings and just about everyone else. They do have a long proboscis which they use to insert into a plant stem If one stays on your hand for an extended period of time, it might try to do the same to your skin, but it’s unlikely to hurt. And really—why would you let it stay there to begin with?