Maxo Kream is a stoic Houston rapper with an unflappable flow. On paper, Lil Uzi Vert could not be a more farfetched foil, whose zany and melodic bars run counter to Kream’s workmanlike raps. It’s fair to wonder what kind of middle ground they might find, and their first collaboration, “Mars” is a silly party banger, which is Uzi’s bread and butter. The lumbering xylophone-laced trap beat and Lil Uzi Vert’s loose, sing-song chorus, (“I take the Xannies on Earth, I will go right there on Mars”) provide the track its sugary core. Kream follows Uzi’s lead, doing his best to match the wonky, triplet-infused pace. While Uzi’s contributions are limited to the hook, his goofiness and energy is the track’s center of gravity: Kream not only cops his flow, but soaks in his sunniness by inflecting his usual somber sound with a more upbeat punch. It sounds like Kream is trying on a happy face, ducking out from the shadows to bask in his guest star’s kaleidoscopic spotlight.