Almost all spiders are venomous.

Spiders are not insects, they are arachnids. They have fangs, and devour their food from the inside out, sucking out the insides. It is also with their fangs that they inject their venom.

The purpose of spider venom is to subdue the spider's prey, almost always insects. Spider venom does not exist to harm creatures, like humans, which are too large for spiders to eat.

The most venomous spider in the world is the Brazilian Wandering Spider. They are extremely fast, extremely venomous, and extremely aggressive. The venom from the Brazilian Wandering Spider is so toxic, that 0.006 mg. of its venom kills a mouse. It is fierce. This is not some wimpy spider that will run away at the first sign of a human, allowing careless hikers to escape a painful death without even knowing they’re in danger. No, these spiders will attack anyone and anything they see as threatening. They are both deadly and aggressive.