The Animus is the device that lets Assassin's Creed protagonists experience genetic memories.
In the modern-day storyline, the Animus reads ancestral memories encoded in a person's DNA. A user enters the machine and experiences the life of an ancestor, allowing the games to move between a present-day framework and historical settings. Desmond Miles is the best-known early user, while later protagonists access memories through related Animus technology and projects.
Eagle Vision is a perception ability, not a machine. An Apple of Eden is one of the series' powerful artifacts, and the Bleeding Effect describes a consequence of prolonged Animus exposure in which users acquire skills or memories from ancestors. The fictional premise draws on the idea of inherited memory, but the Animus is science fiction rather than a real genetic technology. Its name is a stable part of the franchise's terminology from the first game onward.