wild goose chase

A prolonged or chaotic search for something that is difficult to find (often because it does not exist). I've been on a wild goose chase trying to find a bag of Dan's favorite potato chips. Those jerks sent me on a wild goose chase to find a copy of a book that hasn't been released yet!

A futile search or pursuit, as in I think she sent us on a wild goose chase looking for their beach house. This idiom originally referred to a form of 16th-century horseracing requiring riders to follow a leader in a particular formation (presumably resembling a flock of geese in flight). Its figurative use dates from about 1600.

A hopeless search or pursuit. The phrase comes from Shakespeare's Romeo and Juliet: Romeo: Switch and spurs, switch and spurs; or I'll cry a match. Mercutio: Nay, if thy wits run the wild-goose chase, I have done, for thou hastmore of the wild-goose in one of thy wits than, I am sure, I have in my whole five. Although chasing a wild goose seems pointless and doomed to failure, Shakespeare's reference was to horse racing, where a “wild goose chase” was a race in which horses followed a lead horse at a set distance, mimicking wild geese flying in formation.