Euphoria is a game animation engine created by NaturalMotion based on Dynamic Motion Synthesis, NaturalMotion's proprietary technology for animating 3D characters on-the-fly "based on a full simulation of the 3D character, including body, muscles and motor nervous system". Instead of using predefined animations, the characters' actions and reactions are synthesized in real-time; they are different every time, even when replaying the same scene.