Euphoria is a game animation middleware 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. While it is common for current video games to use limp "ragdolls" for animations generated on the fly, Euphoria employs a more complex method to animate the entirety of physically bound objects within the game environment. The engine was to be used in an Indiana Jones game that was later cancelled. According to its web site, Euphoria runs on the Microsoft Windows, OS X, Linux, PlayStation 3, PlayStation 4, Xbox 360, Xbox One, iOS and Android platforms and is compatible with all commercial physics engines. A press release that was enclosed with the second trailer eventually confirmed that Grand Theft Auto IV is the first of Rockstar's games to feature Euphoria. Red Dead Redemption...