When the OASIS had first been launched, it contained only a few hundred planets for users to explore, all created by GSS programmers and artists. Their environments ran the gamut, from sword-and-sorcery settings to cyberpunk-themed planetwide cities to irradiated postapocalyptic zombie-infested wastelands. Some planets were designed with painstaking detail. Others were randomly generated from a series of templates. Each one was populated with a variety of artificially intelligent NPCs (nonplayer characters)—computer-controlled humans, animals, monsters, aliens, and androids with which OASIS users could interact.