“The Joytime II album is a flashback to the original stuff I was putting out back in the day,” Marshmello tweeted, one week before his sophomore LP’s release. “No features. No pop. Just bounce & fun.” That’s an accurate description of “Check This Out,” Joytime II’s second single—a three-and-a-half-minute blast of blinding synths and trampoline-like bass, built around one delirious, titular refrain. Like the masked producer points out, it all bears deliberate resemblance, both spiritually and melodically, to one of his earliest SoundCloud uploads, 2015’s “Pr0.” There is no guest appearance from the sort of major pop star he's collaborated with since vaulting onto the A-List (Selena Gomez, Anne-Marie), nor is it a moody backdrop for a rapper of the day. Just unbridled, unabashed fun.