A 3-headed shark suddenly attacks a group of partying teenagers, killing all of them except one who was on a buoy while the rest of the teens were at the beach. The shark then proceeds to attack the Persephone, an underwater research facility studying the Pacific Garbage Patch. Some of the research personnel manage to escape as the island the facility is based on begins to flood but they face a lengthy swim to reach the relative safety of a nearby boat. Meanwhile, the shark begins to stalk a party boat carrying even more teenagers.
Once again, we’re offered no explanation as to the origin of our Cerberusian antagonist, at least at first, and the inconsistent sizing issue rears its head again almost immediately, with kills taking place within a few feet of water despite the apparent size of the shark in other scenes, unless the beach in question has the world’s steepest and most abrupt drop-off.
We’re back to The Asylum’s slightly more adult shark franchise, so while there’s the usual parade of bikinis, there are also gratuitous topless shots too. It’s an ironic narrative fig leaf to cover the thinness of the plot, which never seems to get its story together. And there are a lot of plot holes to cover so there’s a lot of flesh on show. The 50% increase in SFX costs thanks to the third head seems to have taken a sizable bite out of the wardrobe budget. It seems to be money well spent, though, as the effects work is an improvement on “2-Headed Shark Attack” even if there’s the seemingly endless re-use of the same stock footage of the ocean floor.
The story’s a bit disjointed and the film feels like it changes casts a couple of times as events move from the beach party, to the research station, to the party boat and it’s about the midway point that special guest star Danny Trejo joins the party. For a while, he seems disappointingly inclined to take on the monster shark but eventually, he joins in using a gun which has an apparently unlimited supply of bullets. Not that these bullets do much against the shark so, of course, he has to reach for the one weapon you’ve been waiting for him to use since you saw his name in the credits.
Eventually, the remaining scientists figure out that the shark’s mutation has been caused by pollution and it’s attracted to garbage and they figure out a way to use that to defeat it. While it’s a bit of a hokey way to end the film, there is something meta-textually satisfying that the 3-headed shark is destroyed by its own appetite for garbage. Makes me wonder if there’s a lesson about Shark Weak in there for me.