Ever mistaken a piece of floating wood for a prehistoric monster? No, nor have I, but apparently some do. This kind of faux pas has been touted as an explanation for Nessies for decades as this picture from the Daily Express of the 15th December 1933 demonstrates.
The text reads:
It bobbed up and down travelling at a fair pace - a tree trunk carried by strong currents at Foyers, Loch Ness. France has now heard of the "monster" - "It has the body of a diplodocus and the head of a horse" one Paris newspaper told its readers.
Clearly the Loch Ness Monster in its two humped aspect!