bite this fat beast on his leg 这短语是习语吗,什么意思?

表达一种气愤而已．

"If, God forbid, he is lost, I promise I will, if I manage, I will bite this fat beast on his leg! I promise, I swear to you," Piskun, her face distorted by anger and pain, told AP Television News.

这不是习语！
只是一种用法而已。类似于hunt you down and kick your ass。
语气较重。也可以戏谑用。