For those who are not familiar with Japanese culture, let me explain.
In Japan, there is an idiom called “neko wo kaburu (putting on a cat)”. 
This is used when he or she is hiding his or her true nature and appearing docile. 
You might think it is similar to “wolf in sheep’s clothing,” but it is actually more mildly nuanced. 
It is not used when, for example, a criminal is posing as a harmless civilian. 
“Putting on a cat” is about like “they’re really a little mean, but they’re playing the cute person”.