A wormlike micelle of coarse-grained amphiphilic molecules is simulated with molecular dynamics. We demonstrate that our worm is inherently stable, i.e., it does not depend on periodic boundary conditions for its continued survival, which sets it apart from some, and perhaps even all, previously simulated worms. The worms are observed to buckle under sufficiently strong compression forces. The persistence length and bending rigidity follow from analyzing the thermal undulations of a tensionless worm. System size dependencies of the elastic modulus of the worm, as reported for amphiphilic bilayers, are eliminated by explicitly calculating the arc length of the worm. (C) 2003 American Institute of Physics.