let bigons be bigons

A misspelling of the phrase "let bygones be bygones" which has taken on a meaning of its own.

A bigon is a large fictional sea creature much like a dugong, and a little bit like a narwhale, which misbehaves constantly, however the other sea creatures just let them be because they know that bigons will be bigons, becuase it is in their nature.

The phrase is therefore similar in meaning to the phrase "boys will be boys"