Worlds most dangerous spider, would easily be the Australian funnel web, it is one of the three most dangerous spiders in the world and are regarded to be the most dangerous and deadliest.
Funnel web spiders are medium-to-large in size, with body lengths ranging from 1 cm to 5 cm (0.4" to 2"). They are darkly coloured, ranging from black to blue-black to plum to brown, with a glossy, hairless carapace covering the front part of the body.
Other Funnel-web spiders live in the moist forest regions of the east coast and highlands of Australia from Tasmania to north Queensland. They are also found in the drier open forests of the Western Slopes of the Great Dividing Range and South Australia's Gulf ranges.
Spider bites usually take place on a limb. A pressure bandage should be applied as soon as possible after a bite has occurred. This should be applied as tightly as for a sprained ankle, starting from the bitten area and binding the entire limb above the bite. A rigid splint should be bound onto the limb to prevent limb movement. The patient should be kept as quiet as possible and medical attention sought. If possible, keep the spider for positive identification.