The Spyrat is an outgrowth of Cybrat technology applied on a smaller scale applied to regular rats. The control systems are more rudementry and the brain that they have to work through is less developed, which severely limits their flexibility and range of activity. That said, they can still be directed to move about. They're generally outfitted with a simple spy camera similar to those used on Cybrats, if simplified and minaturized. The main function of which is spying, either on the Things of the surface world or on their fellow Skaven. Generally spy-rats are given to apprentice Warlock Engineers who are on their way to becoming full on engineers mostly tasked with keeping tabs on clanrat activities and factory floors. A few of these aspirants will move on to having Cybrats of their own, though more will end up being eliminated in the petty infighting or for wasting valuable Spyrats through improper use. Another use for spyrats is a munitions, they are outfitted with pig iron bombs, ordered to talk among enemey ranks and are then blown up. This is a useful tool for assasination and situationally a good one for disrupting enemy ranks. Even so given the cost of the control systems and camera they're use in this function is fairly limited.