You mean, providing you with like-for-like proverb, I suppose?
Slim chances, if any.
Maybe there are something on the definition side, though. But then, it doesn´t seem it is what you are seeking.
A bit straying from the topic, but I think that:
When the cat is away, the mice will feel like the cat that got the cream! or
When the cat is away, the mice will be grinning like a Cheshire cat! or
When the cat is away, the mice will think the cat hit the jackpot, and it/she is now a fat cat!
or they will be discussing the situation, of which, one (the cleverest mouse) will say "this is a another breed of cat".