R.O.U.S's are Rodents Of Unusual Size. It comes from the 1980's movie Princes Bride, in the fire swamp scene where Buttercup and Wesley encounter the ROUS's. The rodents are about the size of a large dog.
R.O.U.S are like a Capybara. They are the worlds largest rodent.
von Mina72 18. August 2011