By localizing within the host nervous system, parasites gain a strategic foothold that facilitates precise manipulation of host behavior. Despite diverse mechanisms, unrelated metazoan taxa have convergently evolved to target similar neural pathways. Behavioral changes are sometimes dismissed as nonadaptive by-products of infection, particularly in understudied systems, making it difficult to identify true manipulation. However, growing evidence suggests that such by-products may serve as evolutionary precursors to adaptive strategies. In some groups, such as rhizocephalans, neural interaction appears fundamental to the evolution of the entire group. Recent advances are uncovering specific neural targets, molecular effectors, and precise timing of manipulation. As research moves beyond descriptive studies, parasite neuroscience promises new insights into brain function, evolutionary dynamics, and potential applications in bioengineering.