"Seaman (シーマン Shīman) is a virtual pet video game for the Sega Dreamcast. It is one of the few Dreamcast games to take advantage of the microphone attachment, which in Seaman uses a (relatively) sophisticated form of voice recognition technology. The substantial narration is voiced by Leonard Nimoy in the English-language version.
A limited edition version of the game titled Christmas Seaman was released in Japan on December 16, 1999 alongside a translucent, red Dreamcast. In 2001, Seaman was re-released in Japan for the PlayStation 2 as Seaman: Kindan no Pet - Gaze Hakushi no Jikken Shima (シーマン~禁断のペット~ガゼー博士の実験島), the first edition of which came with a microphone."
Source: Wikipedia, "Seaman_(video_game)," available under the CC-BY-SA License.