As befits a vicious alien antihero, "Venom" is a Marvel origin story of a more cutthroat ilk. Based on the comic-book character created by Todd McFarlane and David Michelinie, this inaugural entry in Sony's hopeful new franchise begins nestled in formula and then gets appreciably wackier from there. Director Ruben Fleischer (2013's "Gangster Squad") embraces this alternately dark and waggish tone, making it easy for the viewer to check their close scrutiny at the door and simply go along for the ride.

Eddie Brock (Tom Hardy) is an outspoken television news journalist who finds himself in hot water when he confronts interview subject Carlton Drake (Riz Ahmed), CEO of bioengineering corporation Life Foundation, with classified information of unethical wrongdoing. Eddie loses his job over his actions, and so does attorney girlfriend Ann Weying (Michelle Williams), from whom he stole top-secret data. Six months later, Eddie has become a broken shell of himself, unable to get hired and unsure of his next move. Whether it be a blessing or curse, his life is irrevocably altered when Life Foundation scientist Dr. Dora Skirth (Jenny Slate) tracks him down with explosive information. Via his space program, Drake has brought to Earth symbiotes—that is, alien specimens which can only survive by attaching themselves to living hosts—and begun sacrificing the weak and needy on potentially deadly human trials.

It goes without noting (but, of course, must be noted) that one such symbiote known as Venom ultimately attaches itself to Eddie, rendering him ravenously hungry and decked with superhuman strength. A man suddenly of two minds—his own, and that of an extraterrestrial who thinks nothing of biting people's heads off as it plots to overtake the world—Eddie must come to terms with his malevolent quasi-alter ego while setting out to stop the cataclysmically dangerous Drake.

There are a few soaring action sequences in "Venom," including a symbiote-swinging motorcycle chase across the steep hills of San Francisco, but where the picture proves most successful is in the unique relationship Eddie forms with Venom, a malleable, baritone-voiced black fungi able to transform its host into a sharp-toothed, smiley-faced ghoul. Adversarial and yet protective, their bond takes a number of intriguing, provocative turns. It helps, indeed, to have someone of Tom Hardy's (2015's "The Revenant") caliber; he ensures the unbelievable is rather plausible. Handsome but otherwise anything other than a conventional leading man, Hardy makes fascinating, offbeat, altogether unpredictable choices in his performance; his Eddie is a more winning yet flawed protagonist than one often sees in these superhero films.

If "Venom" falls into any tried-and-true trap of the origin story, it is the sense that the best is yet to come (in this regard, let's hope for a sequel to expand upon ideas, themes and characters only touched upon here). Michelle Williams (2017's "The Greatest Showman"), irresistible without fail, struggles at times to make more out of girlfriend Ann than is found on the written page. Riz Ahmed (2016's "Rogue One") is effectively cool, calm and malicious as heavy Carlton Drake, but also underserved, while Jenny Slate (2016's "Zootopia") is so terrific as scientist-with-a-conscience Dr. Dora Skirth, one wishes she had more screen time. Much like Eddie and his homicidal parasitic friend, there is a duality to "Venom" as a film. Taking edgy chances, it can be either grim or comedically screwball, complicated in one moment and feeling rather slight the next. There's plenty of promise percolating on a cellular level; with another installment, perhaps a merely good picture can become something more.