学渣中的战斗渣土鳖中的战斗鳖
[xué zhā zhōng de zhàn dòu zhā tŭ biē zhōng de zhàn dòu biē]
Playfully describes oneself as among the worst students but still fighting; also as a very naive/unworldly person (idiomatically translated as a mud crab) that continues to strive. There's humor in admitting inadequacy yet persistence.