The Poisonous Sickle Slug or 'Limax Argentum Maximus' is native to most Western countries, living predominantly in wizarding areas. It secretes a poisonous, sticky mucus which coats it's entire body. The PSS, unlike other slugs, is a meat eater. In order to attract prey it uses it's mucus to attach shiny objects (most commonly dropped change, including sickles) to itself. The goal of this act to attract birds such as magpies. The PSS allows itself to be caught, poison slowly taking effect as the prey returns to it's roots with it's prize. The PSS then makes it's self at home, slowly digesting the bird in a process which can take weeks.
The PSS can be very dangerous, as wizards commonly mistake them for dropped change. If poisoned an adult victim has several days to seek medical attention, while a child could be dead within hours.