Brown Recluse. DO NOT SPRAY THESE WITH POISON! It will not kill them; it only makes them angry and aggressive. The best way to deal with recluses is to put out glue traps. If you catch one alive, release it far away from your house (or it will just come back inside).
Also, just wanted to draw attention to this picture because I feel like a lot of people on here don’t know what a real Brown Recluse looks like. Notice the uniform light brown color, with the dark violin being the only marking. Notice how round its head is; nearly circular. Notice the long and spindly legs. This is Loxosceles reclusa. Take note, and spare the wolf spiders and the grass funnel-webs and the cellar spiders and the brown sac spiders and whatever else you found in your basement. They are harmless. This has been a PSA (public spider announcement)
LOL I enjoyed this PSA!