Mega Snake

Duff Daniels (John T. Woods), the younger, stupider brother of Les (Michael Shanks), can't help himself from stealing a rare snake that's been kept in a jar by a Native American snake dealer (Ben Cardinal), and which has to follow some rules: don't let it out of the jar, then don't let it eat anything anything living, and never fear the heart of the snake. Before you can say, "That's sort of like Gremlins," the snake is out of the jar... (imdb)