This card was included in the Secret Wonders expansion, first released in the Japanese Shining Darkness expansion. A special variant of this card was available at the Pokémon exhibit at the Origins Game Fair between June 26-29, 2008. The card features the event logo. A gold foil stamped "Staff" version was also given to those overseeing the Pokémon exhibit.
The "East Sea" part of Shellos's name is a sub-categorization in order that this card can only evolve into its respective Gastrodon form.