No, I didn’t make it up. There is really a Lake Scugog. As a child, we used to visit family friends on our way home to Ottawa from seeing my grandmother in Toronto.
The name “Scugog” may ben an Ojibwe word meaning “marshy waters.” However, according to Place Names of Ontario by Alan Rayburn, Scugog is a Mississauga word meaning “waves leap over a canoe” in reference, perhaps, to the flooding of the river valley, or more likely, the quickness that waves can be whipped up in winds owing to its shallowness.