Knockers are tiny, parasitic animals native to Gamila's Mauran Tundra. Since their proboscises are not sharp enough on their own to pierce skin, they use tiny, hard extensions to make dents in the flesh. The "knocking" eventually opens the skin, allowing the Knocker to suck blood out of an open wound. They use their tails to hang on to the skin, as well as inject a chemical that renders the flesh around the Knocker numb. This allows the parasite to feed without being noticed.