It's initially established that the Weeping Angels move incredibly fast and attack their victims in the time that it takes them to blink, but then, in The Angels Take Manhattan, Amy and Rory are sent back in time to New York to live in some sort of Weeping Angels farm or battery instead. Why are their victims getting sent back in time, all of a sudden, as opposed to the killing that viewers saw in The Time of Angels/Flesh and Stone two parter? Well, most fans would agree that the "Angel Bob" was just plain weird anyway.