someone in Missouri screwed up, and sent out the Bat-Alert... sort of

"Today, a routine test of Missouri’s Blue Alert system was inadvertently sent to wireless devices statewide. The Patrol regularly tests the Blue Alert system to ensure it works properly when needed. During the test, an option was incorrectly selected, allowing the message to be disseminated to the public. There is no Emergency Alert at this time. The Patrol appreciates the public’s understanding and support of the Emergency Alert program." 

 The alert warned people to look out for a purple and green 1978 Dodge 3700GT with a license plate "UKIDME". That matches the description of the cars driven by the Joker's goons in Tim Burton's 1989 "Batman" film starring Michael Keaton.

https://www.ksdk.com/article/news/local/test-message-mshp-accidentally-sends-batman-themed-emergency-alert/63-0084ef2b-1b95-48fb-8682-6e7626a045b0