The Animus is the fictional machine that lets Assassin's Creed characters experience ancestral memories.
In the series, the device uses a person's genetic memories to reconstruct events experienced by ancestors. Modern-day users lie inside the machine while its interface presents historical locations and events as an interactive simulation. This technology explains how the games move between a contemporary storyline and the lives of earlier Assassins or Templars.
Desmond Miles is introduced as an Animus subject in the first game. Later stories feature different users and versions of the technology, including systems developed or controlled by the Abstergo corporation and its associated organizations.
The Animus is not an artifact such as an Apple of Eden. Apples are Pieces of Eden with supernatural or advanced technological properties, while the Animus is a machine used to access inherited memories. Eagle Vision is an Assassin ability, and the Leap of Faith is an acrobatic technique.