Don’t be alarmed. Although there isn’t anything to give you a sense of scale, I assure you that this is a tiny little spider, less than one centimeter in length. It’s pretty ferocious looking but it’s not going to attack you. There are a lot of spiders and even among the jumping spiders (Family Salticidae) there are a lot this could be. My suspicion is Platycryptus undatus but I’m no expert. I’ll report back here if someone from BugGuide.net can nail it down. As you might have guessed, the red background is the fender of our car. This was taken with the 100mm macro and 25mm extension tube, focused nearly all the way in.