get a wild hair to (do something)
get a wild hair to (do something)
To have an intense, and typically sudden, enthusiasm or zeal to do something. I don't know why Callie got a wild hair to tie-dye all of the sudden, but I did get a cute shirt out of it, so I can't complain.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.