Many people call crayfish (小龙虾) a “loser” because it was once identified in China as an invasive species but ended up as a popular dish. But, most crayfish now are bred artificially (人工养殖). Once they escape, they can bring lots of harm to fields. Crayfish are able to dig holes and can cut the roots of crops in fields. The holes they create, which can be as deep as one meter, may even lead to collapses.