Meet Bloom... he is one of our former foster kitties who spent the Xmas and NY holidays with us. His humans went skiing and couldn't take him with them, so I offered to take him home. He hissed and growled for the first 3 days and after he calmed down, my 3+3 kitties wouldn't want to play with him and they started hissing back at him. But he was nice to humans. We had to make new arrangements so he wouldn't "harras" the other cats while we were at work, but all in all it went fine as he is such a lovely and energetic kitty.