Bert Hughes is home alone in his Manhattan apartment,trying to work out a major change in his trust company when a noisy rat starts scratching around his periphery and he becomes obsessed with exterminating it.By the time Hughes is through,his whole apartment is nearly exterminated-and his friends are keeping their distance due to his rat-mania.Pretty suspenseful and effective rat invasion flick with terrific central performance of Peter Weller.Several memorable moments were the diner table discussion turned to rats and everyone felt uncomfortable;and the end battle with the rat.There are also some very effective jump scenes that were finding the cat on top of the refrigerator and the toilet scene.Overall,"Of Unknown Origin" is a fine animal attack film that deserves rediscovery.8 out of 10.