My mom used to tell horror stories of a friend of hers who fell into a brown recluse nest as a kid. Her legs were cratered by all the bites and the resulting necrosis.Depends on the person. Allergic people could be in for a bad time even from a bite by a mostly safe species. Also some spider venom causes widespread tissue death. It's not life threatening (unless untreated at all), but could end in amputation. Also, they tend to hurt like an MF even if there are no complications.