Five years ago, the DC Extended Universe, the comic book publisher’s first crack at a cinematic universe to rival Marvel’s, was on a streak. Not exactly a hot streak, mind you. In terms of box office, there were several underperformers like the premature team-up Justice League and the smaller-scale Harley Quinn spinoff Birds of Prey. The latter got good reviews, but plenty of bigger hits like Batman v. Superman and Suicide Squad had taken criticallumps. One thing the DCEU had not done in its seven years of existence, however, was produce a traditional sequel. When they finally did, it was a harbinger of doom.