Abstract: The invention disclosed herein is a novel coil apparatus, system, and related method, useful for the mixing and agitation of a powdered substance into a liquid. The coil has features and is configured such that the edges of the coil can reach the inside corners of the bottle or container to provide improved mixing and cleaning of the container. Embodiments of the coil also terminate in a figure or logo that provides a way to mark or brand the product. When combined with a bottle, the system provides a way to store, mix, and clean baby formula, as well as entertain an infant by creating a rattling sound within the bottle.