Rhytidiadelphus triquetrus, the big shaggy-moss or rough goose neck moss, is species of moss in the family Hylocomiaceae. It is often the dominating moss species in moderately rich forest habitats in the boreal regions and the Pacific Northwest. Because of its fuzzy appearance and tail-like shape it is also called the 'electrified cat's tail moss'. Not to be confused with square goose-necked moss, Rhytidiadelphus squarrosus.