The Hitchhiker's Guide to the Galaxy by Douglas Adams.
The sign implies that this creature is commonplace in the world, which in my opinion makes it more ominous. The giant thing itself is creepy, but the car, bloodstain, and sign together make it downright disturbing.
Not that guy but Rozalski is awesome in my opinion too. A lot of his stuff is basically mechs in the 1910s. I really like this stuff
this is all i have on me but he has a ton of stuff on his artstation