over and over again
害群之馬 a black sheep
引狼入室 invite a wolf into the house
open the door to an enemy
狼吞虎咽 wolf down, gobble up
馬馬虎虎 careless, casual,
not very good, so-so, not so bad, just passable
遍體鱗傷 be covered all over with cuts and bruises
be beaten black and blue, be a mass of bruises