The unfortunate results of Crawford Tillinghast's original experiments with his "Illuminator" device haven't deterred others from exploring it's potential. Cruise conspiracy sites on the web and you'll find dozens of stories that paint a disturbing picture of how his creation lives on long after it's inventor's death. Rumors of secret experiments in "stealth" technology using high-frequency energy fields aren't anything new, but the whispers of horrific accidents involving dimensional phasing are all too reminiscent of Tillinghast's unsettling end.
This warning sign is based on the idea that research into Tillinghast technology has considerably refined the capabilities of the original device described in Lovecraft's "From Beyond". Somewhere, hidden behind barbed wire and armed guards, there are labs and hangers where carefully marked areas are surrounded by signs like this.
Just click through for the high resolution version. Print it out on a sheet of sticker paper and you're good to go.