There truly is nothing new under the sun.
Gaffs and monstrous specimens are currently undergoing a bit of a renaissance. Some collectors enjoy the unnatural beasts because they hearken back to a time when the world was filled with uncharted territories and real mystery. Others get a kick out of the slightly sleazy atmosphere that surrounds objects that are effectively lies made real. A third group simply appreciate the artistry that goes into their creation. No matter what their motivation, they've all helped breathe new life into the art of the gaff.
What's intriguing about the current explosion in faux beasts is just how old many of the techniques are. One branch of the field draws heavily on what today is called "outlaw taxidermy", using real animal parts to create chimeras and fantastic mummified creatures. The hideous chupacabras, demon hands, and mermaids of today draw on methods that are hundreds, if not thousands of years old. Stretching a softened animal skin over a skeleton constructed of real bones or a carved armature produces an incredibly realistic effect, something that didn't escape the notice of our ancestors.
A good example of how old such gaffery goes back can be found in this article on the monster mummies of Japan. While the flim-flammers of the west concentrated on creating a multitude of saintly artifacts those in the east were producing an amazing variety of mummified supernatural creatures ranging from demons to kappas. It's no accident that the bizarre gaffs available today have more than a passing resemblance to the ones created hundreds of years ago.