The scary beast in this photo is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It’s the common dust mite, a close relative of spiders. The ...The scary beast in this photo is likely to be lurking in your own home, where it feeds on organic debris, including human skin. What is it? It’s the common dust mite, a close relative of spiders. The dust mite is so small that it is barely visible with the unaided eye, so it’s obviously shown above greatly enlarged.