Nocturnal creatures of the code, surviving on caffeine and the blue light of monitors. The telltale signs are unmistakable—skipping meals because "just one more bug fix," sleeping at ungodly hours because "the code was flowing," and hissing at natural light that dares to create glare on your screen.
The vampire-programmer parallel is so accurate it hurts. Both are immortal in their own way—one drinks blood, the other Stack Overflow solutions. Both come alive at night. Both are mysteriously pale from lack of sun exposure.
Next time someone asks what you do for a living, just hiss and retreat to your darkened IDE cave. They'll understand.