Vipers

First Comes The Slither, Then Comes The Slaughter.

A creature-horror TV movie about mutant killer snakes loose in a small town, driven by survival tension and body-horror threat rather than character depth or thematic weight.

A set of vipers has been taken by scientists to mutate them to make a cure for cancer. As their experiment goes awry, the vipers escape into the woods - they're not only biting people, they're actually killing people, in a little town.