Brian Williams proved his comic stylings once again last night, getting David Letterman to burst into high-pitched squeals. A serious conversation about Osama bin Laden's death (about which Williams recently interviewed President Obama) quickly turned to the whereabouts of Cairo, one of the Navy SEALs dogs. Keeping a straight, news anchor-y face, Williams deadpanned, "He was last, uh, seen on the roof of the Romneys' station wagon." Williams also dismissed any chance of nepotism for his sports-journalist-to-be son, "No, I think the young lad has to fend for himself for a period of two, three weeks, then we'll hire him at the network." Watch the video below for more.