Ugly Mermen are a type of lake monster reported across the world. Other proper terms for the beings would be Ugly Mermaid (for the female variations), and the all-encompassing Ugly Merbeing for the group as a whole. They have been sighted in Thunder Bay, Lake Superior, first sighted in 1782.
Lake Superior Sighting - 1782
On May 3, 1782, voyageur Venant St. Germain was camped on the shore of Lake Superior across from Isle Royale. He was watching the sun set with three comrades and an elderly Ojibwe woman when an unusual creature about 75 yards offshore caught his eye.
It "appeared to him to have the upper part of its body, above the waist, formed exactly like that of a human being" and "seemed to him about the size of... a child of seven or eight years of age." Its countenance "bore an exact resemblance to those of the human face" and it had brilliant eyes, a raised hand of fully formed fingers, and a dark complexion.
Gun in hand, St. Germain was preparing to shoot the creature and save it for science when the Indian woman attacked him. During their tussle the creature disappeared below the water.
Distraught, the woman reproached St. Germain for his wicked intentions. She explained that the mermaid was a god of the lakes and that merely by trying to kill it he would raise a storm powerful enough to kill them all. And for the next three days, the little group of travelers was stranded onshore by gale force winds and crashing waves.
Although St. Germain encountered another fur trader who claimed to have seen a similar creature in the same part of Lake Superior, most people doubted his story. This led him to provide sworn testimony of his encounter with the merman of Lake Superior before a Canadian court in 1812.
One creature that could be considered an Ugly Merman is the Vodyanoy, a frog-faced creature from Russia. Interestingly, a comparison between them and a bearded seal can be made; Bearded seals normally are found in the Arctic Circle but are able to turn up in surprising places, including the Baltic Sea, Japan, and even inland areas of Florida. The Vodyanoviye have been reported around Olonets, Karelia and adjoining parts of Russia and Finland, which are not far off from the bearded seal's general location.Other possibly related creatures include an aquatic dwarf which wears ragged clothing and a broad hat from Central Europe, and a being described as a large amphibian (referred to as a frog by some and a salamander by others) which moves along the current like a log sometimes referred to as a Pskov Crocodile. While this crocodile is less likely to be a seal, it could very well be the simple case of a giant salamander.
A third theorized explanation is that all or some of the reports of these ugly merfolk is female or otherwise tuskless walruses. These walruses may be considered ugly by human standards, with their ample amounts of wrinkled skin and almost human faces. Although they are naturally pelagic creatures swimming throughout the Arctic Circle, it is not unknown for them to be found well off course, and some of these tuskless members may have, at various times, found their way into freshwater habitats through one way or another.