This weekend, the pop punk legends Green Day were on site at SDCC to promote their upcoming feature film, Nimrods. When speaking to press about the upcoming release, front man Billie Joe Armstrong admits he discovered McKenna Grace thanks to Ghostbusters! "The first time I saw McKenna was in Ghostbusters.", says Armstrong. He continues by applauding Grace's role as Phoebe Spengler saying, "Man, she's cool! She would be cool for the movie." Some time later, the Nimrods casting