Wild bantha chase
From Wookieepedia, the Star Wars wiki.
The phrase wild bantha chase was a slang phrase used during the time of the Galactic Republic to describe an activity that diverted from the desired objective. During the search for General Grievous, Obi-Wan Kenobi used the term when speaking to Anakin Skywalker about his mission to Utapau. The mission ultimately transpired to indeed be a wild bantha chase, set up by Palpatine to ensure Obi-Wan could not interfere with his seduction of Skywalker to the dark side of the Force.
[edit] Behind the scenes
The phrase is an obvious derivation of the real-world phrase "wild goose chase."
