Idiom allusions: mud cows go into the sea. Metaphor never comes back.

Idiom origin: Songshi Daoyuan's Record of Jingdezhen and Dengchuan Volume 8: "I saw two mud cows fighting in the sea, and I haven't heard from them since."

According to the source of the above allusions, "Mud cattle into the sea-no news" is the most appropriate.