It could be a wolf spider which has bites are are painful but not poisonous. There are many common house spiders that have these markings.
the pupu spider
Brown recluse
a tarantula!
brown recluse spider
i think it would b a tarantula
look up a green lynx spider
Spiderman's Uncle
The general body plan of an arachnid consists of a cephalothorax (head area), the opisthosoma (abdomen), chelicerae and fangs, pedipalps, eight legs (all of which connect on the cephalothorax), and spinerettes (found on the opisthosoma).
One that is walking backwards
Web-spinning spiders will wrap their prey in a web and then crush its body with their teeth. They then pour digestive juice over the body and liquefy it. ... They help to hold prey while the spider bites it.
That could be anything, there are 100s of spiders that fit that description, please rephrase the question with the area, climate and place that you've seen the spider and a more accurate description. This kind of spider was in my house in PA. It has the body size of about a little larger than a pencil point, in a ball shape, but the body was larger than the avg. size of the head. Has think brown legs. Body is kinda like a black widow.. but brown and much smaller..