CONTAINSSSS SSSSOME SSSSPOILERSSSS
When I first saw the title Lockjaw, I assumed it was actually about the disease, and I therefore immediately looked forward to the director's followups in the genre: Smallpox, Tuberculosis and Amoebic Dysentery. Sadly, this is not a movie about a tetanus epidemic, but yet another horror quickie in which some charmless teens are chased around in the dark by a giant computer-generated snake.
You'd think that after three Shark Attack movies, Shark In Venice, Mega Shark, Mega Snake, Anacondas et al that the creature CG would now be something approaching halfway bearable, but they haven't improved one bit in all this time. The Lockjaw of the title is the nickname bestowed on a giant crocodile/snake demon thing summoned by drawings made by a sacred pencil known as the Kulev Stick (no, I am not making this up). If you use this pencil to draw the monster eating your enemies, Lockjaw will show up and do just that. When a woman is killed in a hit and run, the grieving widower summons Lockjaw for revenge on the those responsible.
Our heroes are, incidentally, more than usually disposable: apart from the pretty girl and the slightly nerdy Clark Kent type, we have two clueless dunces and a second-rate prostitute whose sole purpose is to strip to her underwear and point her bum at the camera. There's also another idiot with a skateboard. Halfway through, one-time rapper DMX shows up, plainly embarrassed (and so he damn well should be), to  explain that the creature cannot be killed, and  kill it with a rocket launcher. I'm not entirely sure how a bloke in a shack has managed to buy a rocket launcher, and I'm not entirely sure how the snake knows precisely who it's supposed to kill, given that the husband doesn't know anything beyond the style of car.
I'm also not sure why they don't just leg it to the nearest city with a ten-storey hotel. But no: we have to have lots of footage of these dimwits wandering around the woods in the dark. This is desperately poor even by the standards of the CG-Megamonster genre: Shark Attack II at least had nice travelogue footage of South Africa, Mega Shark Vs Giant Octopus got by on the sheer stupidity factor. But this just doesn't work at all: you despise the intended victims and you don't believe in the monster. More to the point, it's also a straight ripoff of the far superior Pumpkinhead (Vengeance The Demon). Technically it's fairly perfunctory as well: visually flat and the audio is badly recorded, making chunks of the dialogue incomprehensible. If it's on your rentals queue, take it off now.