Putting stuffed animals in the washing machine can damage them due to the mechanical agitation, which may cause the stuffing to clump or shift. The fabric of the stuffed animal may not hold up well to the rigorous movement and water exposure in a washing machine. Additionally, if the toy has delicate features, such as glued-on eyes or decorations, they may come off or get damaged during the washing process. For these reasons, it's often recommended to surface-clean or spot-clean stuffed animals rather than subjecting them to a full washing machine cycle.