I give you the Camel Spider...
disclaimer: my host is a bit dodgy so this pic may dissapear without notice
They run 10 mph, jump three feet, are a nocturnal spider, so only come out at night unless they are in shade. When they bite you, you are injected with Novocaine so you go numb instantly. You don't even know you are bitten when you are sleeping, so you wake up with part of your leg or arm missing because it has been gnawing on it all night long. If you are walking around and you bump something that is casting a shadow over it, and the sun makes contact with it, you better run. It will instantly run for your shadow, and scream the whole time it is chasing you.
PS. The one on the bottom is eating the one on the top. These are Spiders found daily in IRAQ by our troops. Imagine waking up and seeing one of these b******s in your tent!!