cock-and-bull story
US /ˌkɑk.ənˈbʊl ˈstɔː.ri/
UK /ˌkɑk.ənˈbʊl ˈstɔː.ri/

1.
historia de locos, cuento chino, historia inverosímil
a story that is obviously not true, especially one told as an excuse
:
•
Don't give me that cock-and-bull story about why you're late.
No me vengas con esa historia de locos sobre por qué llegaste tarde.
•
His excuse was a complete cock-and-bull story.
Su excusa era una completa historia de locos.