The catchy headline to this post is probably a bit misleading. The gardener who saw a lake monster apparently left his job and didn’t come back; he wasn’t harmed by the creature in question.
A little more detail from the encounter:
While trimming a hedge beside the A.B. Barrie home above Madrona Beach, Thomas looked out over a placid Lake Washington and saw “the hump.” Almost immediately, Mrs. Barrie saw it, too – a “large, crinkly backed object” swimming south towards Leschi. “It was about 100 feet long but I could only see the middle, which was about 25 feet … I thought its tail and head were submerged.” (Source: http://community.seattletimes.nwsource.com/archive/?date=20010401&slug=lpmonst1)
The Madrona Monster apparently did not hang around for long. There were a few sightings, a picture of an unusual creature (which may have only been a row of ducks), and a report of it later going out to sea.