There's something wrong with Kid Cudi.
He's taken up the guitar, for one thing. When rappers do this, it brings back bad memories of Lil Wayne's "Rebirth." Other bad signs: Cudi's summer arrest for drug possession, and his threat to quit rapping and start a rock band.
Cudi's mopey and mystifying sophomore disc alleviates many of these worries and brings up others. Working the same strange groove Cudi dug for himself on his standout '09 debut, "Man on the Moon: The End of Day," it cements his rep as a depressive stoner with a singsongy mumble and a tendency to pile on enough psychedelic noises, nods to '90s alt-rock nostalgia and well-curated samples to make his albums unceasingly novel, if not necessarily enjoyable.
"Mr. Rager" is smarter, more diverse and more ambitious than its predecessor, though it's claustrophobic and often joyless. A concept album about -- what else? -- fame and its discontents, "Rager" plumbs the bottomless depths of Cudi's existential angst.
There are happy exceptions: The faux-reggae "REVOFEV" is the cheery call to revolution without which no stoner disc would be complete; "We Aite (Wake Your Mind Up)" was made for planetarium laser shows.
But it's not long before "Rager" curdles, turning from moody and atmospheric to dark and self-pitying. The ghostlike Cudi limits his verses on some tracks and is so low-energy on others that it's enervating just listening to him.
"Rager" perks up in the presence of guest stars like Kanye West (on the Weezer-aping "Erase Me") and Mary J. Blige, who provides consolation and cheer on the excellent, space-age-meets-'70s joint "These Worries." When the queen of hip-hop misery sounds happier than you, it's a bad sign indeed.
Recommended tracks: "Erase Me," "These Worries"