In the hit '90s film franchise “Men In Black,” Will Smith specializes in fighting aliens and wiping memories. But on Sunday at the Coachella Valley Music and Arts Festival, he gave audiences a surprise they couldn’t possibly forget. Smith’s unannounced arrival came near the end of J Balvin’s subheadliner set on the main stage, which until that point had been mostly a collection of the Colombian singer’s hits set against a space-themed backdrop. A blowup UFO hung above, glinting in the strobing... Read this story