I recently heard a new urban legend invented by lumberjacks. I have heard most urban legends but this was new to even me.

Lumberjacks believe that if a lumberjack goes into the woods alone he can be attacked by a large monster known as a "hidebehind". They will come up from behind you and strangle you to death. No one sees them because when you turn in their direction the quickly hide behind a tree, hence the name. Whenever a dead lumberjack is found in the woods, it was the work of a Hidebehind.

Thought this was pretty funny. I'm sure it was invented as a joke, but rather amusing. Has anyone else heard of this "cryptid"?

That sounds like a case of gremlins. Unlike the movie (which was hilarious) gremlins are a creature from germany that get inside mechanical objects and screw them up, they are also libel to attack people when seen. Then again, there are several real creature such as cockroaches that will get in machines and mess them up.