For the past few weeks, when my kitty is sleeping, she makes a growling noise and "twitches"(her tail, ears, paws.) Once when she was doing this, I touched her and she woke up abruptly and hissed at me! No changes have taken place at all in her lifestyle, so I don't know what is causing the nightmares if that's what this is. It's worrying me, poor kitty. Do cats have nightmares? If so, what do I do, I don't want her being scared.