Having cats, I know just what the butt wiggle means: preparing to ATTACK!

Then Sheena looks at him and Zen breaks off, goes to the back of the couch again, ha ha haaaa.

Even before that, it is like Sheena knows, she just KNOWS he is up to no good! Her ears never stop, trying to keep track of that crazy kitten.

Zen is small, but he is FEISTY! Do NOT mess with Zen!