One night, Tim's "best friend," his Jack Russell terrier Otis, digs up the ancient and powerful Mask of Loki, which grants the wearer all sorts of antic, shape-shifting powers, as it also transforms his personality, from shy to aggressive. Whether it is Otis or Tim wearing the mask, they become tremendously confident and sexually voracious. While wearing the mask, Tim performs numerous versions (Vegas-style, hip-hop, Country-Western) of "Can't Take My Eyes Off of You," and later that night, inspired by the false courage of the mask, he impregnates Tonya.

The resulting child, Alvey (LIAM & RYAN FALCONER), possesses powers conferred by the mask -- he can imitate behavior he sees on TV, blow up his head like a balloon, fight off evil forces, and most importantly, torment his father, who is left alone to care for him while mom goes on a business trip.

Another father-son relationship is also in trouble. Loki (ALAN CUMMING) is looking for his lost mask and is pushed to recover it by his father, Odin (BOB HOSKINS), the apparently always-angry Norse god of war, death, and poetry. Though he is loudly proud of his other sons, Odin thinks Loki is a failure, and so the son tries extra-hard to please him at the same time that he resents him.

Their strained relationship inverts the one developing between Alvey and Tim, who is afraid of his son's powers. When Tim realizes that the mask might help him impress his boss, Daniel (STEVEN WRIGHT) and so get the chance to create his own cartoon series, he pays more attention to his son and his dog, in order to get hold of the mask. In turn, Loki kidnaps Alvey to force Tim to turn over the mask.

Poor Loki is feeling beleaguered by his father, the blustery god of war and, apparently, storms, Odin (Bob Hoskins looking, well, weather-beaten), who thinks he ought to keep track of valuable and powerful artifacts like the mask.

Loki thinks he's found it in this first scene, and whips up a bit of a frenzied display to frighten the museum visitors so he can abscond with the object. On further inspection, however, he finds it's not what he's after, but instead is a fake. And so he's back to what might be called Loki's Square One, depressed, angry, and resenting the heck out of his father. What Loki doesn't know, but the film reveals to you, is that the mask is currently under paw of a Jack Russell terrier named Otis, who digs it up in his own suburban back yard.

The human owner of this yard and eventual possessor of the mask is wannabe animator Tim Avery (Jamie Kennedy). Prior to getting his hands on the mask, Tim is the standard issue milquetoast workaholic, toiling at his peon's job at a cartoon-making factory, alongside the drearily eager Jorge (Kal Penn) and for the refreshingly -- amid this mess of scenery chewers -- dry Daniel Moss (Steven Wright).

Tim is so fretful about his non-starting career that he's not paying enough attention to his wife Tonya (Traylor Howard), who self-distracts by focusing her energies on babies, specifically, how soon she's got to have one. This is only more pressure for the recessive Tim, of course, (who imagines a trip to the hospital with a pregnant Tonya resulting in an awful scene where she pops out a series of babies like little "ploppy" bullets). A stalemate is reached.

Little does either of them know that their prayers -- for animated inspiration and child -- will both be answered by the mask. Desperate for a costume for the office party, Tim slaps that ancient, filthy, wooden visor on his face and voilą, he's a big-jawed, green-skinned, wholly ugly creature. He's not wildly original like Carrey's version. He's not even vaguely clever.

No, he's Mr. Derivative, a sorry stand-in for an unwelcome sequel, who spends the evening of the party gyrating on a nightclub stage while singing a series of renditions of "Can't Take My Eyes Off of You."

Ranging from country to Vegas to hip-hop, each more vulgar than the one before, these performances include variously scantly clad and bosomy girls and lascivious gestures by Tim, all to show how rowdy and aggressive the mask makes him. Late that night, he heads home, where the wife awaits him in the bedroom. The screen goes black, they giggle, and poof, a child is conceived.

This then, is the titular character, which means that the precise identity of his father is somewhat uncertain. On the one hand, little Alvey (Liam and Ryan Falconer) is surely Tim's baby, cutesy and blond and born without incident following a tedious montage wherein Tonya and Tim cavort, play maracas, and have an ultrasound.

On the other hand, Alvey is the spawn of that mask, or, as Loki calls him, a "chip off the old block," endowed with awesome powers to shape-shift and abuse every living creature that comes within reach of his chubby little hands -- including his dad's "best friend," Otis.

The rest of the film concerns this three-way relation, with Tonya and Odin poking their heads in occasionally to complicate matters for Tim and Loki, respectively. It's nice for little Alvey, who, after being mostly ignored by his father for his first few weeks of life, suddenly becomes the object of everyone's desire.

This even as the child is absorbing the most obnoxious elements of so-called popular culture. Headed away on a business trip, Tonya warns Tim not to let the baby watch TV ("It makes him stupid," she asserts). Whereupon Tim, on deadline, sits the child before the set and hands him the remote.

At first, Alvey learns to sing and dance the "Michigan Rag" like a cartoon frog; afterwards, he learns to torture the dog, who vainly attempts, with mask on, to fight back, only to be defeated by a series of Rube Goldbergian devices -- Otis is pummeled, fire-crackered, slammed into walls and ceilings, flattened in a laundry-wringer, and shot out of a cannon.

From here, it's a short step to tormenting Tim, which Alvey undertakes by a process we might call "gas-lighting" (after the Ingrid Bergman movie). The child pulls all kinds of stunts in front of dad -- talking, dancing, twirling like the Looney Tunes Tasmanian devil, peeing torrents, running up and down the stairs, puking green slime and spinning his head like Linda Blair in "The Exorcist" only to sit quietly and feign infantile innocence when dad tries to get him to perform for the nosy neighbor lady.

The plan works, so far as it goes: Tim loses sleep, believes he's going crazy, and can't get his work done ("My son is the devil!" he wails). That Alvey might consider such meanness as a goal appears to be a result of his affinity with Loki -- it's "mischief," rather than out-and-out torture. Or so the child seems to think.

When Loki shows up to repossess his mask, he's so impressed with the baby that he decides he wants him too. And so the struggle over family dominion will make a man out of Tim, a better dad out of Odin and a better son out of Loki. And Alvey? He still gets to beat up the poor dog. "Son of the Mask" rates as a 1 out of 10.