Like the words deer and sheep, the singular and plural forms of the word "Pokémon" do not differ, nor does each individual species name in short, it is grammatically correct to say both "one Pokémon" and "many Pokémon". The term "Pokémon", in addition to referring to the Pokémon franchise itself, also collectively refers to the 493 fictional species that have made appearances in Pokémon media as of the recent release of the newest Pokémon role-playing games (RPGs) for the Nintendo DS, Pokémon Diamond and Pearl. The name Pokémon is the romanized contraction of the Japanese brand, "Pocket Monsters" (ポケットモンスター, Poketto Monsutā ?), as such contractions are very common in Japan. The franchise celebrated its tenth anniversary on 27 February 2006, and as of 1 December 2006, cumulative sold units of the video games (including home console versions, such as the "Pikachu" Nintendo 64) have reached more than 155 million copies. Pokémon properties have since been merchandised into anime, manga, trading cards, toys, books, and other media. Originally released as a pair of interlinkable Game Boy role-playing video games, Pokémon has since become the second most successful and lucrative video game-based media franchise in the world, falling only behind Nintendo's Mario series. Pokémon (ポケモン, Pokemon ?, IPA: ) is a media franchise owned by video game giant Nintendo and created by Satoshi Tajiri around 1995. You may be looking for Monster in My Pocket. For the oncogene once called Pokemon, see Zbtb7.