蛇蝎为心蛇蝎心肠shé xiē wéi xīn

as vicious as a viper or scorpion
❍ 便是蛇蝎心肠，不似恁般毒害。(无名氏《抱妆盒》二) Even vipers or scorpions could not have been so vicious.

蛇蝎为心shé xiē wéi xīn

蛇：指毒蛇。蝎：毒蝎。即心肠如同蛇蝎。形容坏人的心肠狠毒。也作“蛇蝎心肠”。