"Tarantula" is one of those words that "everybody knows", but is tricky to pin down scientifically. Yes, it means a big hairy spider, but there are more than one type of these, they have different behaviours, and some are (much!) more poisonous than others. Nowadays it generally refers to the family Theraphosidae, so when I say tarantula, I´m referring to them.
In Brazil there are, believe it or not, 170 different species of tarantula. They generally live in burrows and stay fairly close to the hole, hunting at night. They eat more or less anything they can kill, but they are themselves hunted, particularly by the huge Tarantula Hawk wasp, whose bite causes instant paralysis, but not death. The unfortunate spider is then dragged away to be used as a larder by wasp larvae.
Sometimes they do go walkabout. Males go looking for females, and it is said that they leave their holes when storms are expected, which does seem reasonable. Tarantulas can, I can testify, climb glass. This has the rather neat advantage that they can be photographed from below, which somehow makes them even more frightening.
Despite their fearsome appearance, and reported aggressiveness, tarantulas in the Americas are not so dangerous. The pain of an tarantula bite in the Americas is supposedly not particularly intense and indeed in Mexico the Tzeltel reportedly encourage tarantulas to bite tumours as a sort of chemotherapy.
In contrast, perhaps the only "attractive" characteristic of tarantulas is their furry appearance, but ironically, that is the only thing humans really have to fear. Don't stroke one! They are covered with special barbed hairs which they can flick off at a predator (or prey, or just someone they don't like) which can be incredibly irritating to the eyes and throat. Interestingly in Bahia powdered tarantula tea is recommended for asthma, which sounds like a guaranteed asthma attack - perhaps just the threat of it "cures" the poor patient until he is out of sight of the healer.
If you really must play with a tarantula, go here.......
By the way, the arachnophobic description in the title is from Rudyard Kipling. In 1927 he visited the world famous venom research institute at Butantan, Sao Paulo, and left a characteristically pithy description, but more of that another time.