Oh it’s a recluse. They are very common here. Old timers used to put crickets or lizards in their closets to eat them. The good thing is that unless you are cleaning out a closet you don’t have to worry too much about them because they hide. I keep those sticky flea traps with lights out all the time just in case. Having one in the car is a first.
My brother-in-law almost lost a hand from a bite from one. He was into junk/flea market sales and kept a garage full of junk to sell. He was sorting through some clothes and one bit him on the thumb. His thumb turned black and it took several surgeries and skin grafts but he kept his hand.
If you apply, or have doc apply or prescribe, a shaped piece of a nitroglycerin patch around a recluse bite relatively soon after it occurs it reduces it to just itchy bite. Earlier is better, but works even after it starts getting ugly.
The mechanism that causes the necrosis is a fraction of the venom that causes vasoconstriction and this isolates the area from blood flow which would just dilute and move the bulk out to the liver and other cleaning organs. Putting the patch on dilates the vessels and short circuits the envenomation.