Goliath Bird-eating Spider
OK, now this one does look legitimately frightening, even to a spider fancier. Part of the tarantula family, Theraphosa blondi, found in Venezuela, the Guianas and Brazil, is the veritable Andre the Giant of spiders. The biggest specimen ever captured, a female named Rosi, weighed a formidable 6.1 ounces (175 grams).
Velvety black in appearance and equipped with fangs that are three-quarters of an inch (20 millimeters in length), the Goliath usually feeds on insects such as crickets and beetles. Despite its name, it rarely feeds on birds, but it's capable of killing and consuming bigger prey, like small mammals and frogs. If you get bitten by one, though, the effect is probably no worse than that of a wasp sting [source: Natural History Museum].