What is play to the cat is death to the mouse.
More Danish Proverbs:
Vice is learnt without a schoolmaster.Danish
Every light hath its shadow.
Danish
God permits the wicked; but not for ever.
Danish
When every one minds his own business the work is done.
Danish
It needs but slight provocation to make the wolf devour the lamb.
Danish
It is too late to throw water on the cinders when the house is burnt down.
Danish