Kingdra is a large, seahorse-like Pokémon with a tightly curled tail. It is covered in blue scales except for its yellow, compact belly scales. There are thin spines with a single branch atop its head and thin, white fins under its cheeks. Its thin snout is powerful, allowing squirts of water jets with devastating power to be fired. Two-pronged fins extend slightly past its cheeks. On its back is a white fin supported by thin, blue spines similar to the ones on its head.
The yawn of a sleeping Kingdra is powerful enough to create undercurrents capable of destroying small ships. Should it decide to emerge from the depths of the ocean, Kingdra's strength can create large whirlpools and sea-born tornadoes on the surface. Because of its immense power, Kingdra often hibernates deep in uninhabited areas of the sea to rest and build up its energy. When a storm arrives, Kingdra is said to awaken and wander about in search of prey.
Kingdra physically debuted in Dueling Heroes, under the ownership of Christopher. It lost to Totodile in the first match of the Whirl Cup after it plugged up Kingdra's snout, causing excess water to build up inside, thus sending it flying across the stadium.
Kingdra is the only Dragon-type Pokémon introduced in Generation II.
Kingdra and its pre-evolutions share their category with Dratini along with its evolutions, Salamence, and Goodra. They are all known as the Dragon Pokémon.
Kingdra is based on a weedy sea dragon, but still shares many characteristics with regular seahorses. The fact that it dwells on the sea floor while creating whirlpools may be based on the mythical monster Charybdis. Its secondary Dragon-type may be a reference to a Japanese name for seahorses, 竜の落し子 tatsu-no-otoshigo, which means "dragon's child", and to the legends of Ryūjin and East Asian dragons, where they are said to bear power over the seas of the world, live on the floors of deep bodies of water, and are also known for their weather like ascensions into the heavens.
Kingdra may be a combination of king and dragon or hydra (a mythological sea creature).