A parasitic mass originating from China, which latches onto the arm and/or penis of (typically) a male human. Known to make incessant noises which cause insanity or other personality disorders. Treatable, but difficult to cure. Large cause for STDs.
The parasitic mass is in the same class as the Hirudo, or leeches.
Peter: Oh god, what's that thing hanging on Matt's arm?!
Patrick: Oh, you didn't know? Matt has Hargrove's Syndrome.
Peter: I hope he can be cured!