No one wants a child to be bullied.
In reality though, some kids will bully. They will tease. They will ridicule. You don’t even need to be a cat.
I was ridiculed for being brown. I couldn’t help my skin but ridiculed I was.
I was ridiculed for not being able to run or climb a rope. Not just by kids. The teachers and headmaster joined in on that too.
I was stocky - not fat - just stocky. Guess what?
No one wants a kid to be ridiculed/bullied. I suspect pretending to be a cat or fish or whatever would attract exactly that.
It doesn’t make it right. It makes it all the more likely. And indulging it may set children down a path that will only bring them deep sadness.