pitch a curve
pitch (one) a curve (ball)
To do something unexpected or deceptive that surprises, confuses, thwarts, or outwits someone. Her confidence and fact-of-the-matter answers pitched police a curve during their questioning. I had only been reading the textbook instead of going to classes, so a few of the questions on the final exam really pitched me a curve ball.
pitch someone a curve(ball)
Fig. to surprise someone with an unexpected act or event. (Referring to a curve-ball in baseball. It is the route of the ball that is curved, not the ball itself. See also throw someone a curve(ball).) You really pitched me a curveball when you said I had done a poor job. I did my best. You asked Tom a trick question. You certainly pitched him a curve.