蚍蜉撼树pí fú hàn shù(lit.) an ant trying to shake a tree (idiom); (fig.) to overrate oneself; to overestimate one's capabilities
蚍蜉撼大树pí fú hàn dà shùlit. an ant trying to shake a big tree (idiom); fig. to overrate one's own strength; also written 蚍蜉撼樹|蚍蜉撼树[pi2 fu2 han4 shu4]