Powers: Dr. Hydro could transform himself into water vapor. He was amphibious, able to breathe on land or underwater. He does not possess gills, but rather is able to extract dissolved oxygen from water via specially adapted pores in his skin.
He used a variety of weapons utilizing "Hydrocules", which were some type of enlarged water molecules, or condensed water, or something. He had lots of other Kirbytech™ weapons, such as a high pressure gun able to fire condensed water spheres; a giant atom, which could serve as an energy prison that turned its prisoners force into resistance right back at them.