The Animus is the virtual-reality machine used to access genetic memories in Assassin's Creed.
Within the series' fiction, the Animus reads inherited memories encoded in a person's DNA and presents them as an interactive simulation. Modern-day characters use it to experience the lives of ancestors, allowing the games to move between contemporary settings and historical periods.
Desmond Miles is the best-known early user. Abstergo Industries places him in an Animus to investigate the memories of Altaïr Ibn-La'Ahad in the first game. Later stories introduce updated Animus models, portable systems, and related technologies such as the Helix platform.
The concept is fictional and does not describe how real genetics or memory work. A frequent mix-up is calling every virtual system a Helix: Helix is a later entertainment and simulation platform, whereas the Animus is the core memory-access device. The Apple of Eden is a powerful Isu artifact, not a machine for viewing memories.