This is the Demodex, which is part of the arachnid family. These beings, which measure between 0.3 and 0.4 mms, live on our faces. In your hair, eyelashes and eyebrows... They run around unnoticed, unlike other, more visible spiders that one is more tempted to crush.
But they don't only run around! They sink deeper into the pores of your face. And the older you are, the more likely you're able to shelter these charming little critters. Even if they don't cause any serious harm, they can still cause dermatological problems if they're present in too large quantities.