丑人多作怪人心隔肚皮
[chŏu rén duō zuò guài rén xīn gé dù pí]
The phrase '丑人多作怪' (literally means ugly people tend to be weird) is a colloquial expression often used to criticize those perceived as physically unattractive and acting abnormally. '人心隔肚皮' refers to hidden feelings; what people hide in their hearts. Overall, it describes someone acting oddly while concealing their true intentions.