A Seriously Beneficial Bug

It's not really a bug per se.  It's a spider, a really small jumping spider that has a taste for mosquitoes.

This little guy.  In real life, two could sit on your thumbnail, side by side.

It appears he has a taste for human blood, but being who and what he is and entirely too small to actually get it from the humans themselves, he's got to get it by eating mosquitoes.  His fangs are really tiny, but a mosquito's feeding equipment is well adapted to get blood from animals including humans.  The spider's is well adapted for getting nourishment from bugs.  And when this spider smells blood, they go into a feeding frenzy, killing more and more mosquitoes without necessarily stopping to eat them or even if they've recently had a blood meal.  He just goes on a rampage.  They even seem to show preference for Anopheles mosquitoes, the ones most associated with transmission of malaria.

So if you've got a fear of spiders, maybe you could dial the dread back a notch.  This one is nothing but beneficial to humans.

This breed also shows a preference for being around humans.  Researchers discovered the spider would spend more time in close proximity to a sweaty sock - that is to say, close to something that smelled like humans - than in close proximity to a clean sock.  Given the option, the spider would choose to be near where it perceived humans might be.  Probably expecting an unwary mosquito to come blundering by, I reckon.

If you see a spider, don't hurt him.  He might be doing you a favor.