Hiya Woolfie, welcome to MFK,
I wish I could believe in Nessie but as the old truism goes, "Extrodinary claims require extrordinary proof". This particular guy doesn't even have the excuse of believing in an honest illusion, he is a deliberate liar and fraud.
If you are amused by this kind of thing check out some of the Cryptozoology sites that are around, some are full of fakes, some are unexplained case histories that don't claim any answers, but my favorites are the "monsters" that get explained, like the partially decomposed basking sharks being thought to be sea monsters.
My favorite story was a few years ago when some handliners started reporting sea serpents off the Isle of Man, They said that monsters with huge eyes were stealing hooked fish from their lines and several refused to fish that area. researchers caught a few of the "monsters", they turned out to be large gurnards that had been brought into the area by a current shift, The color variety that was being cuaght can flash eyespots on thier fins, when veiwed through several feet of dark water all you see is a pair of eyes acouple feet apart looking back at you, It happened to a couple people, the story got exagerated, and a legend was born.