Speed Force
In the fourth issue of "Infinite Crisis", Barry Allen comes out from the Speed Force, along with Johnny Quick and Max Mercury, to help his grandson Bart deal with Superboy-Prime, taking the villainous teen with him in the Speed Force. Bart Allen appears wearing Barry Allen's costume in Tokyo near the end of "Infinite Crisis" #5 to tell the heroes that Superboy-Prime has escaped the Speed Force. Bart again reappears in "Infinite Crisis" #7 in Barry Allen's costume to combat Superboy-Prime once more.