Travelers to Crater Lake National Park could tell the Old Man of the Lake when they spotted it.
The "old man" is actually a tree stump, estimated by some to be 34 feet or so long, with 30 of those feet under water, that bobs perfectly upright around the lake. Spotting it from the crater rim might be difficult at best, but those who take the interpretive boat ride around the lake itself are likely to come upon it, as I did earlier this summer.
Those who know say the "old man" has been bobbing in the lake since at least 1896. It's believed that the hemlock tree was knocked into the lake by a landslide off the rim walls, and that rocks tangled in its roots help stabilize it in an upright position.
Comments
A couple of issues of Nature Notes from Crater Lake describes a bit about the history of the Old Man of the Lake, including a couple of old photos (one of which is below).
1938: http://www.npshistory.com/nature_notes/crla/vol11-3c.htm#3
1996: http://www.npshistory.com/nature_notes/crla/vol27e.htm#4