You should take a person at their word, the old adage states, when without instigation they admit to a deep, dark flaw. On the title track of the Shins’ perplexing new album Heartworms, James Mercer sings, “Well I guess I'm just here to test your patience.” Boy, does he make good on that bit of honesty. Heartworms isn’t exactly an instance of total self-parody, a chunk of red meat thrown at his rabid haters. (Those who loathe the Shins, I think, foremost despise Zach Braff and Garden State.) No, these songs are too melodic and specific to brush aside. An expert satirist couldn’t achieve this kind of sonic quality and lyrical detail, and get both so right. And yet, the record does approximate a middling SNL lampoon of what made the Shins’ past albums indelible to some and infuriating to others. It undercuts itself at every turn, often enough that I wonder if it’s meant to be a goof, an end-in-itself genre provocation, rather than a wholly disappointing misfire.

Part of me leans toward the former hunch, that Mercer is explicitly pranking us with an inviting take on Bob Dylan’s Self Portrait, or a pop-oriented redo of Lou Reed’s fan-shedding Metal Machine Music. Of all things, the album shares a name with the parasitic organism that would kill my dog, should I forget to feed her a monthly chewable tablet. I guess its title also seeks to evoke the notion (and a sensitive variant) of the “earworm,” that invisible string of notes also called a catchy melody, which burrows into your brain and refuses to let go. Melodies do abound here aplenty. But what makes Heartworms so maddening is how eagerly it buries them under a landfill of aural waste.

James Mercer has claimed the following were inspirations for the Shins’ fifth LP: Missy Elliott, the sci-fi series Black Mirror, Ariel Pink, Merle Haggard, and the Danish astronomer Tycho Brahe. If one zig-zagging thread links them all, it’s an iconoclastic spirit, which Heartworms delivers in all the wrong ways. Mercer takes the eccentricity of Chutes Too Narrow, an important part of its greatness, and amps things up to outright zaniness. This, in and of itself, wouldn’t be a problem in more capable hands (see, for example, Pavement’s once-dismissed, gonzo masterpiece Wowie Zowie). Rather than send delirious pop tunes through a weirdo prism, to bend and twist compositions on the margin, he chooses to stifle them outright, straightjacketing good songs in layers upon layers of unnecessary studio-work. The result is an overcomplicated mess, masquerading as Pet Sounds — and a tension headache, even for a sympathetic listener like me.

The previous Shins album, Port of Morrow, was a minor triumph, an example of Mercer at his most majestic. So I wanted to like Heartworms, and at first I did. But every additional spin brought fresh irritants. The classic-pop tropes with which Mercer embellishes these songs (bings, boings, and tra-la-las aplenty), and the suffocating fatness of their instrumentation, can’t cover up a fundamental, emotional flimsiness. These are songs that simply don’t stick. Chutes Too Narrow succeeded not thanks to its eccentricity, though it was odd, but because of its songcraft, which was direct and human. The closest Heartworms gets is on the remarkable exceptions of “Fantasy Island” and album-closer “The Fear”. And yet, potent as they are, both still seem overcooked.

Despite the glorious melodies hidden within so many of these tracks, like the opening duo of “Name for You” and “Painting a Hole”, huge potential is undermined by ham-fisted executions and depths you could wade through. Part of me hopes this is a lark, that Mercer is testing his audience, toying with our expectations. Port of Morrow was so excellent, and so recent, that maybe this isn’t an omen of things to come. The Shins may get a bad rap, but this time, it doesn’t seem unfair. C PLUS