Taratulas are large carnivorous spiders that inhabit desert or tropical areas. While most are varying shades of brown or black, a few support rich colors such as cobalt blue or deep purple. They range in size from palm-size to dinner plate.
A tarantula's bite is painful, but not dangerous, although it's probably more traumatizing to have a huge furry spider pounce on your hand and bite you than to simply get stung by a bee.
Tarantulas differ from other "true" spiders not only by their size, but by their mechanics. A tarantula's fangs are located to be used in a vertical grabbing motion, while true spider's fangs work horizontally in a pinching motion.
There are rumors that tarantulas will not cross velvet, but I have yet to see whether they truly have a physical aversion to it, or if it is simply an old wives tale.