Hassie (Hassie of Nagara River) is an aquatic cryptid that has appeared in Gifu Prefecture,Japan. Note that the cryptid that appears in Lake Hamana in Shizuoka Prefecture is sometimes called Hassie as well.
Description[]
On June 10, 1986, two teachers working at different junior high schools were driving by the Nagara River when they noticed a fin-like object protruding from the river's surface. Upon observing the creature, they discovered that it was a ray-like creature about 2 meters long and 1 meter wide with triangular fins. The creature swam in the downstream direction.
Some saltwater rays, such as the red stingray, are known to travel up rivers, but Gifu Prefecture, where Hassie was spotted, is odd in that it is an inland prefecture, far from the ocean. The triangular fins that Hassie has are not characteristic of freshwater stingrays, so it is unlikely that a domesticated freshwater stingray was released into the river.
Hassie's name comes from the city of Hashima in Gifu Prefecture, where the sighting took place.