An arkan sonney (literally lucky urchin or plentiful pig) is the Manx term for hedgehog. In Manx folklore it is a type of fairy creature which looks like a pig with long hairs. They are said to bring good luck to one who catches them. For this reason they're also called "lucky piggies". They flee human beings. They live in the wild, are faster than lighting on land and have feathered wings that can be up to one and a half times their body size.
It was said by the old folk that if you catch a lucky piggy you will always find a silver piece in your pocket.
Another tale from A Manx Scrapbook by Walter Gill describes it as a white pig seen by a child near Niarbyl, Isle of Man. She wanted her uncle to help her catch it but he refused and it got away. In Dora Broome's Fairy Tales from the Isle of Man, the pig is described as white with red eyes and ears. In that story the pig can change size, but not its shape.