#OnThisDay in 2007 after @DCOfficial.bsky.social #52ComicSeries ended the #weekly #Countdown #comics seriesDebuted with #51 #countingDownBackwards to #DCUniverse #0 #FinalCrisis prelude #Darkseid #DonnaTroy #JasonTodd #JimmyOlsen #KarateKid #KyleRayner #MaryMarvel #TheTrickster #PiedPiper AWOL #Atom