By size, they are the 2nd fastest creature on earth, first being the cockroach. Sulifugids are closely related to scorpions. If you look at the pics, you'll see that instead of pincers, they have those 2 big legs they use to shovel whatever they can into those big jaws. They are really fun to keep, and can tackle huge prey. If you have an extra 10g laying around, try setting up a little habitat. They're really easy to keep.