A local legend among the Nez Perce tribe states that when the Nez Perce and Blackfeet were at war, the daughter of the Nez Perce chief fell in love with the son of the Blackfoot chief. One night, the couple took a canoe from the Nez Perce camp and rowed out on the lake. Eventually, the rival tribes realized what was happening and set out after them. The monster then came up out of the lake and attacked them, killing them all. To this day, the Nez Perce do not venture out on the lake.
An article was written in the local Wallowa Chieftain newspaper on November 5, 1885, detailing a local resident's encounter with the monster:
"A prospector, who refuses to give his name to the public, was coming down from the south end of the lake on last Friday evening in a skiff shortly after dusk, when about midway of the lake he saw an animal about fifty yards to the right of the boat, rear its head and neck up out of the water ten or twelve feet, but on setting him it immediately dived.
He ceased rowing and gazed around in astonishment, for the strange apparition which he had just seen, when it raised about the same distance to the left, this lime giving a low bellow something like that of a cow. It also brought its body to the surface, which the prospector avers was one hundred feet in length. The monster glided along in sight for several hundred yards. It was too dark to see the animal distinctly, but it seemed to have a large, flat head, something like that of a hippopotamus, and its neck, which was about ten feet in length, was as large around as a man’s body.
Now this story may have been coined in the imagination of the narrator, but he was very earnest in his recital. However, it is a known fact that there is a tradition among the Indians that the lake has a big sea cow in it, which on one occasion, many years ago, came up one evening and swallowed a young warrior and his dusky bride as they were gliding over the surface of the lake in a canoe. And to this day an Indian of the tribes who formerly frequented its shores cannot be induced to go upon its waters. The lake has been sounded to the depth of 270 feet, and it is a bare probability that some monster does inhabit its unexplored depths."
Since then, there have been few sightings of the creature. In 1932, two residents of the area saw the monster, and described it as longer than their 11-foot boat. Irene Wiggins, who lived along the lake, claimed to have spotted the creature many times between 1945 and 1983. She described the monster's head as "a big, black thing, like a hog's head", and estimated it weighed hundreds of pounds.
In 1950, three people saw two monsters feeding on fish, the first being 16 feet long and the second being 8 feet long.
In 1978, a couple claimed to see the creature twice. First, they saw "three hump-like protrusions break the surface of the lake, albeit briefly." Second, they "watched an approximately twenty-foot-long, snake-like animal circle a certain portion of the lake for several minutes." In 1981, two men spotted the monster.