The Lake Monona Monster has been seen in Wisconsin since the 19th century. One of its sightings was by a couple that were canoeing in the lake in the 1860s. Upon accidentally bumping a floating log with one other their oars, the water began to churn underneath their boat. The log suddenly moved and submerged itself under the waves.
One of the canoers later wrote about what they had seen:
“This was a monster of some sort, we have no doubt. We were not too long in deciding that retreat was the better part of valor and we resolved to say nothing about the matter.”