This scaly creature inhabits the lake from which it takes its name in Dickson County, Iowa. It is said to be dark colored and to have a huge head. However, its body is said to resemble that of a fish, which is perhaps what it is. It has a reputation for attacking boats, using its head as a weapon. This results in the hapless boatman being catapulted from his boat, enabling the Monster to devour him in a grisly meal.
Just what this creature is, if indeed it exists, one cannot say. It seems to me it may be simply a large pike or sturgeon. But what do I know?