Good Job, didnt think someone would get that so quick. Love those things. lol, just saw after the question someone made a camel spider thread. YOUR TURN.
most spiders are cannibalistic and will eat each other if they encounter another. Also, wouldn't which ever spider survives the encounter be the one that out thought the other?
cant think of the species name but are you thinking of the spider that taps on other spiders webs to trick them into coming close and then jumps at them to kill?
edit: is it the Portia (hunting) spiders. (portia labiatus)