It is a Saturday night at Carrollton Station, a tiny club with a floor that shakes on hot nights. The Bluerunners, a band from Lafayette, Louisiana, scorches the crowd with a bizarre swamp-thing hybrid of Cajun barn-burning rhythms and rockabilly. The dancers are elbow to elbow, back to back, soaking each other with sweat rivulets of joy. It is February, Mardi Gras 1990, but it is hot and the floor is shaking.

A blue runner is a Southern snake that hides in blackberry patches unti...