恶龙不斗地头蛇

Explanation: Snakes: metaphor bully people. Although the analogy is very powerful outsiders, but also no match for the local forces 　　Usage: As object, attribute; for oral 　　Source: Ming Feng Meng, "Awaken the common saying," VII: "Tai Guanren Hugh said full words! As the saying goes: the dragon does not fight snakes." Thesaurus:  Thespesius No pressure a cock on his own dunghill (=a cock of the dunghill), Masiakasaurus When not fighting snake