  A wolf Working Hand in Glove with a Jackal 狼狈为奸

  A wolf and a jackal often went hunting together. Once they came to a sheepfold the walls of which were firmly built and too high for them to get over. Then they had an idea: Since the wolf had long forelegs and short hindlegs while the jackal had short forelegs and long hindlegs, the wolf stood on the neck of the jackal, and the jackal stood up on its hindlegs. In this was the wolf climbed over the wall to where the sheep were. 
  狼和狈常常结伴出外伤害牲畜。有一次，狼和狈一起来到一个羊圈外面。羊圈很高，又很坚固，叼不走里面的羊。狼和狈就想了一个办法：因为狼的前脚长后脚短，狈的前脚短后脚长，狼骑在狈的颈上，狈用长长的后脚站起来，狼就用长长的前脚攀住羊圈，终于把羊叼走了。

  
  This idiom is used to describe doing evil things in collusion with others. 
  "狼狈为奸"这个成语比喻坏人互相勾结起来干坏事。