I must admit I'm arachnophobic, while gathering this list I felt creepy and my hair starting to raise just seeing this spiders. While gathering the list I find them fascinating just by reading wikipedia but still they are CREEPY. Spiders are the most abundant predators in the world and have adapted to almost any imaginable habitat except for the sea, giving rise to countless species many of which remain unknown to science. So here's the list of 6 Venomous Spider that you should not mess and they will fight back.
From Wikepedia: The hobo spider (Tegenaria agrestis) is a member of the genus of spiders known colloquially as funnel web spiders. It is one of a small number of spiders in North America whose bites are generally considered to be medically significant. Individuals construct a funnel-shaped structure of silk sheeting and lie in wait at the small end of the funnel for prey insects to blunder onto their webs. Hobo spiders sometimes build their webs in or around human habitations. Although this species of spider has a reputation for aggressiveness, they will normally avoid contact with humans. Most bites occur when the spider is accidentally crushed or squeezed by a human. The spider's venom is strong enough to cause considerable local pain and possibly necrosis.