pitch a curve

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.
See also: curve, pitch