Somehow I suspect you already know this story. For the past 4 or 5 years I've had a small fiber optic Christmas tree that the cats totally ignored.
This year, Cassy has taken exception to the little thing and has attacked it daily. So far as I can tell, it is just the same as it has been all along, but although Cassy is bigger than it, it MUST be thwacked daily.
CATS!