The gameplay of the Pokémon series of role-playing video games involves the capture and training of many of fictional monsters called "Pokémon" and using them to battle other trainers. Each generation of games builds upon this idea by introducing new Pokémon, items, and gameplay concepts. Some of the general ideas were featured elsewhere before being introduced in the games; double battles appeared in the anime long before appearing in the games, and Pokémon abilities are similar to the Pokémon Powers first seen in the "Pokémon Trading Card Game".