ㄅㄢㄓㄨㄢㄗㄚˊㄐㄧㄠˇbānzhuān‑zájiǎo

搬砖砸脚
  1. 磚頭自己比喻找麻煩自食惡果 做事再三考慮一些搬磚砸腳」。

to hurt oneself by one's own doing, to boomerang, to shoot oneself in the foot (idiom)​