Spines are frequently considered to be an important physical defense against predators. This experiment shows that spines do not always function successfully as physical protection. Using natural predators and prey (the drilling muricid gastropod Nucella lamellosa (Gmelin 1791) and the mussel Mytilus trossulus (Gould 1850)) this experiment used artificial spines in different configurations and densities to try to assess the role of spines as predatory defense. The presence of spines did not inhibit the predator from choosing ornamented prey. Greater spine density did not improve the probability of surviving a predator encounter. Although mean handling time increased to some extent with higher spine density, the outcome of the encounter was the same. Presence or density of spines did not deter predators from attacking prey, and experimental prey with greater spine-density experienced greater mortality than did specimens with fewer spines. Drillhole dimensions differed slightly between the treatments, probably as a consequence of difficulties for the gastropod to maneuver its accessory boring organ (ABO) in between the spines.