Ghostbusters: Frozen Empire's Surprise Star on Changing the Series' Ghost Rules

Ghostbusters: Frozen Empire has a lot of characters it's juggling, and one of the most important wasn't even actually in the film's marketing. That would be Melody, played by Gossip Girl's Emily Alyn Lind, a 16-year-old who quickly strikes up a friendship with McKenna Grace's Phoebe Spengler. The twist? She's a ghost...