“I am walrus, hear me blubber” might be the mantra of Kevin Smith’s “Tusk,” an utterly bizarre, weirdly compelling story of manimal love that stakes out its own brazen path somewhere between “The Fly” and “The Texas Chainsaw Massacre.” And yet there’s much good humor, too, in Smith’s latest low-budget indie, which reunites the director with his “Red State” star Michael Parks, who’s gifted here with the sort of tailor-made, career-capping role most actors die waiting for Quentin Tarantino to give them. He’d be worth the price of admission alone, but “Tusk” has other surprises up its pelt, including a pseudonymous special guest star who gives the movie a shot in the arm just when it needs one. Twenty years on from “Clerks” — and amid occasional threats of retirement — Smith has delivered a left-field surprise that ranks among his very best work, though how such an oddity plays in today’s marketplace (where innovative distrib A24 releases it Sept. 19) is anybody’s guess.

The 74-year-old Parks has played in more than 100 films and TV shows (including several by Tarantino) over a 50-year career, but he’s never had a part quite like the one Smith has concocted for him — one that plays knowingly off the actor’s own status as a veteran farer of the turbulent Hollywood seas, a go-to second lead and character player who never quite cracked the A-list. In “Tusk,” he’s Howard Howe (or so he claims), a real-life ancient mariner with a lifetime of strange adventures behind him and many tall but true tales to tell.

That proves an irresistible invitation to Wallace (Justin Long), one half of a popular Los Angeles podcasting duo, who’s traveled to the wilds of Winnipeg for an exclusive interview with a flavor-of-the-month YouTube star (“He turned down Oprah!”) who, unfortunately, turns out to be literally dead on arrival. Scrambling for a backup plan, Wallace catches sight of a room-for-rent ad bearing a digest of Howe’s intriguing bio, and so sets off to meet the well-traveled mystery man, who in turn sits waiting for him with the practiced patience of the spider waiting for the fly.

Parks has such light in his eyes, fire in his belly and a mellifluous purr in his voice that it would probably be a pleasure to watch him recite the Manitoba phone book, but Smith (who adapted the film from a story he first conceived with longtime collaborator Scott Mosier on an episode of their own weekly podcast series) supplies him with considerably richer fare. Rolling about his cavernous manor — tucked, naturally, just far enough back from the main road to diminish any screams — the wheelchair-bound old man holds his visitor rapt in his raconteur’s spell, each story bearing a talismanic connection to the objects that line Howe’s shelves and mantles: a whisky bottle that belonged to Ernest Hemingway here; a large walrus baculum there. That last item triggers a harrowing memory of shipwreck and survival at sea, in which the young Howe found his life saved by a less likely companion than the giant tiger from “Life of Pi”: a compassionate walrus he nicknamed Mr. Tusk, and whose eventual loss he grieves to this day.

Well, absence makes the heart grow fonder, and it soon become clear that Howe’s five-decade estrangement from Mr. Tusk has him hankering for a reunion — one that Wallace might just be able to facilitate. And that, really, is all one should know before seeing “Tusk,” in which the more the reels tick by, the clearer Howe’s designs on Wallace become, until the avuncular recluse stands revealed as some unholy hybrid of Victor Frankenstein and Josef Mengele. (Though it’s part of the complexity of Parks’ performance that he always makes Howe seem more than an outright monster, a man who believes he’s acting from a place of love and mercy.)

Meanwhile, back in L.A., Wallace’s broadcasting partner Teddy (Haley Joel Osment) and girlfriend Allison (Genesis Rodriguez) get wind that something is awry and set off on a rescue mission, eventually joining forces with a weary but unfailingly polite Surete du Quebec detective named Guy Lapointe, who’s been tracking Howe for years and offers valuable insight into the man’s peculiar m.o. Lapointe is the movie’s other inspired creation, played fastidiously and with great, sly humor by a Hollywood chameleon (credited only as Guy Lapointe) who hasn’t seemed this playfully engaged in a role in many a tentpole. Osment, too, is very effective as the caring but not entirely loyal friend, as is relative newcomer Rodriguez as the semi-neglected s.o., all of which keeps the pace up during what could have been dreary procedural interludes.

But “Tusk” unquestionably belongs to Parks, and to Long, who seems at first to be cast in a mild variation on his well-traveled, shit-eating-grin-hipster persona, but who ends up having the most emotionally and physically demanding role of his career — one that, for reasons which become clear as the movie progresses, restricts him from using many of an actor’s usual expressive tools. To put it in the movie’s own, inimitable terms, he goes “full walrus” and then some, building to a finale that’s sincerely touching in a way no one watching a movie with this plot would have any justifiable reason to suspect.

Although we’re a long way here from the View Askewniverse of Red Bank, N.J., “Tusk” runs thick with the director’s house blend of highbrow literary references, lowbrow bathroom humor and fast-food fetishism. As in “Red State,” Smith opts for a sleek widescreen look (courtesy of d.p. James Laxton), with far more attention paid to framing and fluid, motivated camera movements than on his rough-hewn early features. Makeup designer Robert Kurtzman’s impressively transformative practical effects are virtually a co-star unto themselves.