Land Leaches are common on the trails after every rain. This one hasn't had a meal recently, and is inchworming its way across the guide's hand looking for a good place to bite. It injects anti-coagulant and anesthetic, making the bite painless. After it has its fill and swells up to peanut size, it drops off. While the vicitm may bleed for a couple of hours, there is no itching and little swelling. We didn't get any bites, but others we met did.