"He contrived many ambushes to entertain us, like a fierce hunter for its prey." One thing, it should be: "...like a fierce hunter for HIS prey." Aside from that, there is nothing grammatically wrong with this sentence, but I think it could be clearer. "...like a fierce hunter for his prey" seems to denote fearsome, vicious, or aggressive-- not 'entertaining.' If you choose one direction (fierce) or the other (entertaining), it might read better: "He contrived many ambushes to entertain us, like a crafty hunter luring his prey. " "He contrived a series of ambushes to demoralize us, like a fierce hunter for his prey."